Well so I decided to put in a AGM battery in my car that came with a EFB. I figured well I just change the settings in the BCM and all should be dandy. But the BCM for some reason doesn't charge it past 80%SOC still and for the MK3.5 there doesn't seem to be a setting to change that.
So I might just be killing the battery quickly. Is there anything I can do software/firmware wise to get the max SOC behaviour to go up?

Now let me tell the long story.
I bought this 2016 car with 180k/km used about 4 months ago cheap. Being the enthusiast I normally am with things and since I bought it cheap I did a complete service on it. In so I decided to put in a AGM battery. Changed the Profile in the BCMii Main to match the Battery and just drive.
Driving like that for around 2 months until it got cold and had a no starting issue. Digging around in forscan I realised there is another battery setting in the BCMii which is basically the same as in BCMii Main which might have been the culprit. It charged the AGM in the EFB profile the whole time which made it  undercharged for months but it only became apparent when it got cold. So now both profiles are correct. I pulled the battery and did a wall charge. Put it back in at 100% and reset the Battery SOC. The voltages and SOC do corelate now. Before it was all messed up. But even though it corelates It is no good. The SOC only goes up to 80% in the car but with a higher voltage which is the correct voltage for the AGM 80%. But not the 95% desired SOC for AGM.

Hmmm would messing with the Asbuild to the Job if it is actually exposed?

				Battery Management System (BMS)
726-06-01	****	xxxx	xxxx	BMS SOC Critical Cfg	(percent)
726-06-01	xxxx	****	xxxx	BMS SOC LSoff Cfg	(percent)
726-06-01	xxxx	xxxx	**xx	BMS SOC Max Cfg	(percent)
726-06-02	**xx	xxxx	xxxx
726-06-02	xx**	**xx	xxxx	BMS SOC Off Cfg	(percent)
726-06-02	xxxx	xxx*	xxxx	BMS SOCQF Check Enable	0=Disable, 1=Enable, 2=Disable2

Will go down and check. The setting is not exposed in the normal adjustable settings

Yeah ok my BCM seems to be a bit older. Last line I get is 

726-06-01

****

xxxx

xxxx

So basically it either works with the AGM profile it came with. Or it will perpetually be stuck and 80% and needs to be topped up from time to time until I jump back to a regular EFB.