Ingenuity not working?

Using Enchanting Concentration to make Algari Mana Oil R3. It costs me 82 concentration per craft. I have worked it out as 12 crafts (60 oils total - not including multicraft etc). I would have 16 Concentration left.

I’m maxed out in Supplementary Shattering and tooltip says when Ingenuity procs it should refund 100% of the concentration used (82).

I’ve just completed a batch and got 1 Ingenuity Proc, however I was still only able to craft 12 times with Concentration, and sadly only came out with 61 R3 oils! In my head I should be able to craft 13 times, and get a minimum of 65 R3 oils?

I was using mirror powder, and of course shattered an essence. I have more than need r2 Storm Dust, using best quality reagents option so I don’t believe the negative amount is coming from a craft using R1 Storm Dust.

Am I not mathing correctly, doing something wrong, or getting scammed? Cheers.