I'm also wondering about the 2 coat paint system & whether you can actually wipe down walls without going through to the primer coat or leaving a mark. We have a puppy so need to be able to clean occasionally.
I believe Solver is supposed to be a good brand & I'm trying to get a bit more info from the SC. My son built with another company 2 years ago who used Wattyl 2 coat system & you can't clean the walls without it showing.
If you pick a darker colour you'll find they automatically upgrade it to 3 coat, which i think, says something about the level of finish in a 2 coat finish. My local Solver dealer said Solver & Wattyl are now merged - same company. Said paintshop also recommended one level of gloss up from Boutique's standard full matt (I can't remember the actual name, 'semi-gloss' perhaps). The full matt look is cool with designers now but a bit less friendly to look after. I'm currently renting in a new flat with full matt finishes & it marks sooo easily. I haven't asked Boutique for a step up in gloss yet so not sure if they'll ping you for a 'custom colour'. I expect they buy their paint supplies in bulk but perhaps it's not a big deal.