Actually about time to consider replacing the bolts to SS type. Not very expensive at few bucks a piece.. for peace of mind because structurally alot of weight still supported by the rafters.
Wood rafter still usable if theres no termite history. Metal roof structures should be coated with "cooling aid paint" i.e. intumescent paint so in case of fire, the steel will not "buckle under heat" so easily.
Read more here: https://www.ifsecglobal.com/fire-protection...ire-protection/

SS bolts and nuts just cost around RM5-6 a pop for 1/2" size..as a price refernce. Best to replace like for like.
https://shopee.com.my/4%E5%88%86(1-2'&#...5689.4356684848

Sharing my ID company quotes, pending their reply on what kind of wires/sockets they are using

They revised because of "raw material" price increase? RM52 to RM100 seems quite a big jump.
Yours is quoting based on Mega Kabel, the most expensive already =)
I'm still waiting for my primary contractor to revert on the brand of cables they are using, if it's some no brand/china cable, it's not a good comparison already.

If you are still actively looking for electrical quotes, you can try these 2 people ( I met them earlier this week for site survey and am waiting for their quote). I'll be insisting on using Caramay / Fajar cables with the new quotes :
Ah Hui : +60 12-228 4543 (my close friend recommended this guy. The friend also did major reno, knocked down except beams/pillars)
Chai (Kejuruteraan Letrik Cahaya Baru) : +012 219 7368 (he did repair works for me previously at my current condo, seemed honest and knows what he's doing)

Both nice young chaps (30s-40 years old), chinese speaking (which is a bit tough for me, as I'm half banana )

I noticed your list does not include (just in case you missed it out):
1. Water heater points?
2. Garden lights, gate pillar lights
3. installing lights, fans, AC
(I'm getting separate AC installers)

btw, the electricians are not my friends yar. One of them (Ah Hui) was recommended by a close friend of mine =)
good luck with the reno! and feel free to hijack this thread anytime. meant for all to share, compare and learn.

Generally cables increased price by around 25-30% (since March 2021)
for 2.5mm Mega Kabel/Caramay used to be around 85, now its 120-125
for 4.0mm used to be around 136, now around 163 online

Since your work volume is quite a big sum, there are such things called double sockets that will make end user life easier (just pay the variation few bucks in parts pricing). It will not "overload the cables" at all under normal usage (whole circuit MCB protected). Singles are used for small jobs to earn the few bucks "per point"..if all installed double how to earn (since your job is a big job the contractor should be pound smart and not penny foolish)

Since your work volume is quite a big sum, there are such things called double sockets that will make end user life easier (just pay the variation few bucks in parts pricing). It will not "overload the cables" at all under normal usage (whole circuit MCB protected). Singles are used for small jobs to earn the few bucks "per point"..if all installed double how to earn (since your job is a big job the contractor should be pound smart and not penny foolish)

[attachmentid=10878179]
Ref. above diagram and also to the sections 3.4-3.5 [attachmentid=10878180]:
13A SSO need a full set 2.5mm² LNE (3-wires) from DB into the socket.
"Looping" (connect from next door existing socket into a nearby new socket) is the radial diagram.

For lighting point, they are cheaper since the wire length is shorter and the cables are thinner at 1.5mm².
Earth is optional if not using those old type fluorescent tube with the magnetic brick choke, and is usually not fitted, but its alright to have it fitted.
Typically lights do not come with earth wire, but for the old fluorescent tube with magnetic brick choke, this choke is like a "transformer" that need to be bonded to earth, while the lamp casing is not required to be earthed. Modern LED tube does not use the old magnetic choke so no requirement under section 7.5.

Usually (in standard 1 light point 1 switch, no staircase switching) it is:
single wire L from DB box to the switch, from switch and end at light point.
single wire N starting from light point and return to DB box.
Bare channel usually refer to the "casing kosong" for tube lights. Casing kosong meaning NO starter and NO choke (since these dinosaurs are not required) - LED tubes do not need the dinosaur parts to work. A bare casing will be able to operate LED tubes perfectly, usually these casing kosong is described as for use with LED-only.
Yes. As per the diagram the only extra effort is that the box hole need to be hacked bigger, and you need the double socket with matching box. Itu sahaja.
Identical wiring effort as per single socket as there's only 3 holes to be wired.
Per diagram.. technically 3 runs from DB box, able to individually control 3 different bulbs on a 3-gang switch (in any possible permutations of ABC on/off)  are considered chargeable as 3 points.
Technically this will be branching out 8 lights from one light point. Something like Xmas lights, 100 little bulbs on a single run, but with the RF controller you can turn on each of those 100 little bulbs individually. However, you still need some short wiring from the central controller to the 8 lights (like spider legs).

Most welcome 

If my understanding is correct you just need the wires sticking out where the light should be unless you're going with the tube lights?
(this pic shows a light point, fan point c/w hook, and doorbell point out the wall) but essentially the core idea is a ready-to-hook-up point.

[attachmentid=10878182]

Sometimes.. if the main con not clear about what's going on, then the subcon may add in all the side dish upgrades which are not needed or totally don't make sense.

I noticed your list does not include (just in case you missed it out):
1. Water heater points?
2. Garden lights, gate pillar lights
3. installing lights, fans, AC
(I'm getting separate AC installers)