QUOTE(hanishoney @ Jul 11 2016, 04:44 PM)
Babies should NOT be left in the carseat for longer than
90 minutes each time, BECAUSE the carseat is not lying flat. Babies should lie flat most of the time. However, lying flat in the car is NOT safe if there is a car accident, because the 45 degree angle as per your carseat's indicator, protects your baby's entire spine in a car accident, like a rocking "cradle when the bough breaks" in the song rockabye baby song.
So just tell your auntie that baby will most often be in his crib/floor/cot lying flat at home, not in the car. BUT this angle is
necessary in the car. If you have to drive for more than 90 minutes with your baby, break the journey up so that baby gets out of the carseat for half an hour or so every 90 minutes.
Once your baby has head control, you can extend his/her time in the carseat to two to four hours, but every two-four hours, still need to let out to stretch and move about. In fact, adults should also get up/out and stretch/walk around every two/three hours to extend lifespan.
More info:
http://www.babycentre.co.uk/x554834/is-it-...in-his-car-seatYou can also tell your auntie that baby must NOT be fed lying flat. Babies also need the 45 degree angle for feeding to make sure that if they vomit (reflux is very normal for babies), they don't accidentally swallow back their vomit and choke.
hanishoney can really be our Malaysia CarSeatLady or CarSeatGuy

Time for a little review of my Diono Radian R120 car seats after using for a month.
Details:
-Car Seat Models: Diono Radian R120 (2x)
-Car: Honda City 2015
-Car installation position: Side and middle of car rear seats (rear-facing position)
-Usage: Side rear seats is for my 2.5 year old toddler and middle rear seats is for my 9 month baby
-Using ELR belts and locking clip for both child car seats instead of Latch to save width space
-Top Tether is clipped on the Diono Tether strap for both child car seats
-Bought Diono angle adjuster and installed it at the child car seat (side rear seats). This is to free up some space of the front passenger seat.
-Bought and installed two Diono Dry Seat Protectors to minimize any accidents (pee, vomit etc)
Review:
The child car seat is really narrow. After installing two child seats rear facing at the back, an adult can still sit at the back comfortably. It uses full steel frame so it is quite safe but it is heavy. This car seat can rear-facing till 20.5kg or 112cm, forward-facing till 36kg, booster mode till 54kg or 144cm. It has a chest clip to ensures the child stays safely and correctly positioned within their harness. The car seat can easily be folded if not in use. It is also crash test certified.
However i also find some cons. This car seat has very few paddings due to it is narrow and there is almost no head protection. I should have bought the Diono Radian RXT for the little extra head protection. However the Diono Radian RXT also have some cons. Some say the child's shoulder may hit the head wing when they grow older and the head wing may interfere with the car seat belt in booster mode. The Diono Radian R120/RXT is very tall so rear-facing can take up alot of space therefore i bought the Diono Angle Adjuster.