As they will probably never sell all available tokens, and have to burn alot of them in the end for sure, it shouldn't be a problem at all to increase the amount of MIO tokens of early investors.
The total possible monthly payouts will be spreaded to all MIO-token holders according to the amount of MIO they have. So if there would be a compensation for early (esp. FIAT) investors, that would just mean, that the late investors get "less" for their investment, than they actually would get right now.
I think that would be a fair solution for a community like this.
I would get about 2000 MIOs more (that's about 40%) if i would have done my investment today with 15% discount, instead of investments with 35% and 30% discount.
That's what i'm irritated about, and i think it's not fair at all and should be considered by miner one.