Heroes trial issue

I encounter similar, do the math on what energy or power you have to spend and choose the path you can complete, but then when getting to the last creature that cost 7 energy it indicates you need 12 more power just to move on, not needed to spend. Then you can’t even use the exchange right next to it and there is no other exchange. Just overly complicated and disappointing to be just one spend point away from finishing the run. Why, why is that necessary? Oh but wait, then if you did have enough power the last one that cost 5 energy requires to have 15 power, what the heck, ludicrous. I recommend don’t take the upper path unless you have near 55+ power, count that extra 12, I mean now 15 power even though not needed to spend. Give a thumbs up if you encounter this unnecessary complicated bs. Really needed those 10 hero tokens, so disappointing.