BQ40Z50-R1: Battery Pack rated capacity vs actual capacity

Tool/software:

Hello

I had a few question in regards to battery pack actual cell capacity vs rated capacity

our pack is made of up 4S2P 

the 2P is 2ah cell which would give us a total of 4ah capacity for the pack

but in the battery pack spec it says "rated capacity "3.2ah"

any reason as to why we derate the capacity?

Here's few pic showing what i described 

Second question what does RSOC & ASOC values map to in Bqstudio?

third question:

i know for lithium cells it's not recommended for it to be charged 95%

so if our cell is actually 4ah and it's been derated to 3.2ah does this mean we can charge it >95% 

as that extra 5% will not bring us to 4ah?

Fourth question:

how's this derating done?

Regards

Jonathan Kabangu