How many childchains can ardor handle?

I know there isn't and hasn't been a lot of childchains on Ardor, but current code seems to limit it to 10? (10 "slots" per block) or could there be 100 childchains like polkadot can do 100 parachains with the current code already?

If there was more then 10 childchains, could the number of "slots" (or ardor tx's) per block be increased to not have chains waiting their turn to get a slot and process transactions or is there performance issues with doing so?

Adding a child chain requires a hard fork anyway so at any time during a child chain deployment we could use the opportunity to also change any of those limits. Those are just configuration parameters that can be easily change on code but require a hard fork.

Okay, so there isn't a performance restriction right now. Just the hard coded values that can be increased with the hard fork.