Okay, got my copy in hand, and looked over the Ebb/Flow power.
Near as I can tell, the "double tap" tactic is that Magnus described is perfectly legit. Granted, it's a fair investment of XP (10 for base power, at least another 30 to get the two Control upgrades in question, plus 20 for the Strength upgrades, and then however much XP to get Force Rating to 2 to have a snowball's chance of getting all three effects to trigger).
Now, to get the full monty of healing 1 strain plus adding 2 advantage and 2 successes to your next check means you'd need 5 Force Points, putting that into the realm of Force Rating 3, or Force Rating 4 if you want to regularly accomplish it without being too reliant upon using those dark side pips on your Force dice. Taking out the Strength upgrades and settling for just the extra success and advantage requires 3 Force points. At FR 1, you're probably looking at just two of the three effects at best, or maybe one of them if you've got the appropriate Strength upgrade.
So it's a cool trick, but it's not going to veer anywhere close to game-breaking without a substantial investment of XP, and by that point the other PCs should have some pretty awesome tricks of their own to call upon.