The robopacers go .1 or .2 over their nominal rating on hills, both up and down. The multipliers apply to drops, not XP. I was doing a long easy ride and really racked up the drops when I stayed with one pacer the entire time. Every 5 minutes the mulitplier increases, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5 and then stays at 2.5 as long as you maintain the pace. XP will get you gear, but drops will get you bikes and wheels. I have enough drops now to purchase 3 or 4 top frame/wheel combos. But unless you race in Zwift, does it really matter? I "bought" a gravel bike the other day because I was going to be on a gravel road but it didn't matter to my ride. I was still riding at the same watts and burning the same calories, and it didn't matter if the generated scenery went faster or slower. What did matter to me though was that I was fast on the sprints, coming in in the top 5 on two of them, and a third I was eighth, all times out of around 250 riders. Not bad for a 69 year old. There's no way though that I could beat the top scores as they are always way faster, so much so that I think some cheating occurs on these.