Actually, the last proposal only came out after 2 years after the one before that:
Technically if we are looking at increments of 25 seats year over year, we should be looking at 200 Seats right now.
But this is more about what the floor of entry is that is why adding 25 seats, for now, is good.
@marbar With respect to blocktimes there should be no increase from the data I have at hand (from external networks), Technically we could have 300 Seats and there should be no difference in blocktime.