Mods at the bottom are loaded last. This one changes the cost of uber transforms, so if you want to change it again, you would need to put your mod below 5X. Check the output log too to see if your yaml was loaded correctly.

Thank you for your response :) it seems if I change the viablefarmingfactor to more than 1 it increases planet population cap but at some point hangs up and gets stuck processing the turn

Yeah, it's not meant to go higher than 1. If you want to increase the population cap beyond 1, you basically have to go into planetsizetypes and increase the cap globally, except that then increases it for all biomes, so you have to go to every other biome you don't want to increase and do a corresponding decrease of the farming and industry factor and leave the one you do want to increase at 1.