WARNING: Read me before buying OOO, page-102

Correct, you need to be confident of a short term movement above what the futures market is pricing.

Regarding the exact math, it's a little more tricky than just comparing one month's future price to the next since it is rolled over a 5 day period, 20% per day. I also believe OOO rolled over to the June 2020 futures contract from 7th of April finishing on the 14th, so yes - you've already taken some of the hit, luckily the contango wasn't as bad 7-14th of April as it is now.

To calculate this, if you create a weighted average of the two contracts, where the weight of June increases by 20% each day from the 7th April ending 14th April, then deduct the cumulative roll yield for each day - i.e. 20% x (Jun futures price - May future price) - you'll see you get a return very similar to OOO over that time frame. I had a crack and almost got there, granted I'm not including any management fees, or impact from hedging. Dark blue is my calculation of the daily return, light blue is actual change in OOO net asset value, and the greys are the two WTI futures contracts.