I see, you don't understand how those batteries are labeled. 5036108, model taken out of the fxtec battery is in reality size of that battery.
50 means it's 5.0 mm thick.
36 means 36 mm width
108 means 108 mm length
That's why I found this battery, it meets all the size criteria and that's why it has very similar but not the same capacity. Those keyboards has 1450-1450 mAh batteries because they are twice as thin than the fxtec battery. And that's why you are wrong, sorry.
Why there is no 3200-3150 mAh batteries in this size on the market? Because batteries with tha