I had not seen someone test a 520/Plus battery in a standard H. I stand corrected, but at the same time, I have not seen any posts by anyone who has purchased the higher volt batteries to get longer flight time on the Typhoon H. Considering the much higher price of the 520/Plus batteries your ROI of the extra time in the air may not be worth the additional investment.
Also, neither the Yuneec OEM charger nor the EV-Peak/Morpilot DY-3 charger will work with those batteries... you would need the DY-5 model charger or a 3rd party LiPo charger and cables specific to the 520/Plus.
Since the pricing of the UltraX Replacement are less than half of the Plus batteries, IMHO you will still have the least cost per minute of flight time from the UltraX batteries.