I'll play along... i lowered my BHE to 10% just to see how much it'll lower the OG once we've taken into account the new lower brewhouse efficienty.

The OG is 1.032 still.

The bug here is that trub loss is not tied to BH eff in any meaningful way. It's actually tied to Mash eff ... the mash eff is calculated using the BH eff, trub loss, etc. Those volumes are user editable fields and not linked directly, they all adjust mash eff up/down to make "bh eff" equal the losses you've inputted.

I bet the addition of sugar is using a mash eff of 100% because it's extract and the efficiency is not variable. Then the PPG is calculated with the batch volume and not the total ending boil volume.

I'd be further curious if PPG for grains is being calculated off batch volume and not ending boil volume... because most people just adjust BH eff number until their preboil OG matches what they got brewday and assume that's their mash eff.

This theory can be tested... substitute your 5lbs sugar for 5lbs 2row at 1.036 PPG. Your OG is 1.036 at 100% BH eff. I noticed my mash eff jumped is 200% which is impossible, and makes sense here because i need to extract 10g of wort to have a 5 gal batch and 5 gal of trub loss. But to keep a 100% bh eff i'd need to get twice as much sugar out of those grains than possible. DRop BH eff to 50% and my mash eff goes to 100% and my OG is back at 1.018 which is what i'd get if i diluted the wort with double the water. This all seems to check out, because Bh eff is tied to the volumes and mash eff.

For sugar, we have no variable mash eff.. it's 100%. So if we add trub loss we need to drop the PPG gained from the sugar. Rather, not drop the PPG.. but divide the PPG we got from the sugar over the volume... we get less points as we dilute it away with extra 'trub loss'. I can't lower the BH eff number because it'll jack with my mash eff on the grains in the recipe. Plus, the BH eff adjustment doesn't affect OG with sugar ... I really just need the points calculated for the lbs of sugar and divide by the total ending volume. There's not really a way to link BH eff into that...

Suggested fix -> use ending volume for calculating PPG by sugar unless I specify adding to "secondary" or something later when the volume will match the batch volume. If i'm adding 5 min into the boil it should be based off "ending boil volume" which includes trub losses that i'll suffer as i drain into the fermenter

Workaround -> Do the math yourself for PPG ... or just live with it. You'll only be off by a percentage (the percentage difference is post-boil volume vs batch size)