Workshop marked up price to cover for:
a) their higher purchasing cost as they normally source it from neighborhood spare part shops (i.e not main dealer / stockist).
b) their purchase is on credit term instead of cash basis
c) labour to re-do or claim warranty / hassle provided in case of complaint

One may purchase it and install it separately due to workshop tied up with certain brand of lubricant or their supplier (i.e spare part shop). Do note, certain part shops only carry certain brand of brake pads...etc..(for eg: Mintye is everywhere but one prefer Akebono/ Trestor/ TRW)

No doubt it is secret on name and location of shops which are the main spare parts dealer / stockist. I have share the list as below.
https://forum.lowyat.net/index.php?showtopi...&#entry95023713