Did you have a MYWHopper+? If so, then yes, the plus would require a second plus usage to go to the other park. Even though you had a MYWH+ the hopper applies to the main parks only. Any of the plus usages are not hoppable, and would use two entitlements. So if you went to MK and DHS in the same day, thats 1 main park admission used. If you went MK to BB that would be 1 main park and 1 plus entitlement. If you went to MK, BB, TL and WWoS that would be 1 main park, and 3 entitlements. I'd suspect that many of the water park guests have + entitlements, and not standalone water park tickets. It's only $15 to add the plus to a hopper ticket, vs almost $60 for the single day.