I know its a new function but when I hook a basic Water Pump to a single pipe it stops filling the pipe completely past a number below the new maximum. I lined the pipes up to test this:

-Copper Pipe/Iron Pipe/Stone Pipe: 100 of 100

-Bronze Pipe/Steel Pipe: 150 of 150

-Plastic Pipe/Brass Pipe: 206 of 225

-Titanium Pipe/Ceramic Pipe/Tungsten Pipe: 206 of 325

-Nitinol Pipe/Copper Tungsten Pipe: 206 of 500

Interestingly, when I first noticed this it was Copper Tungsten only filling to about 156 off a Water Pumpjack. And if I put four pipes down it would thin out to 100, and if I removed a pipe the one behind it would fill to roughly double the previous amount, but I couldn't get the pipe to fill completely.

I at least hope this is a bug, Fluids in this game have confounded me for years and are always where I just end up with massive headaches. Still, I'm trying to build a blueprint balancing around lines of construction, and larger pipes in theory would help (it would also help if the Infinity Pipe could be set to higher than 100, but that seems more difficult.)

Edit: It seems to be working today. Though I did download a few new mods to try to help deal with the flow problem.