If you use their pool addresses then it depends on the demands on that algorithms. You can go to their marketplaces to check.
I guess I'm "renting" my power to them.
By 'renting' to them you do not have the power to select the algorithm therefore you can only be rewarded for what jobs they 'assign' your gpu's to do. In my logic at least.
But is there a different power that the gpu's have in regards to running a different algorithm on them?
If yes this would justify the difference in payout.
You do have the capability to point to a specific algorithm, turn off the ones that you dont want to do.
Shit, this is news to me. Any clue how?
Reference below; hopefully this is what your are looking for and will help.
https://www.reddit.com/r/NiceHash/comments/6f910l/how_to_change_nicehash_miner_algorithm/