Parti-Gyle Gravities

I am getting into the method & planning to do a English Barleywine & English IPA parti-gyle method the first week of July. I am writing out my recipes and playing with gravities. Just making sure my logic (and calculations) are on par. I average a 65% efficiency with batch sparging.

English Barleywine - 1st runnings (mash temp 156 F)

18# Maris Otter (38 x 18 / 5) = 136.8
4# Mild Malt (37 x 4 / 5) = 29.6
2# Caramalt (34 x 2 / 5) = 13.6

180 x .65 = preboil gravity 1.117


English IPA - 2nd runnings (mash temp 154 F)

180 (potential) - 117 (1st runnings) = 63 (remaining) x .65 = 40.95 = 1.041 attribute from original mash
add 3# Maris Otter (38 x 3 / 5) = 22.8 x .65 = 14.8
add 2# Honey Malt (37 x 2 / 5) = 14.8 x .65 = 9.62
add 2# Flaked Oat (37 x 2 / 5) = 14.8 x .65 = 9.62

1.041 + 0.014 + 0.010 + 0.010 = 1.075 expected preboil gravity

Thanks in advance for input!

I'm not following your calculation. The total potential is 180 points. If your efficiency is 65%, you'll get 117 total. Why do you think (re)mashing (without many conversion enzymes) will raise your efficiency to almost 88%?

PS 2 lbs of Honey Malt in an IPA will be strange. Have you done this before?

1.041 from original grain bill on 2nd runnings - was planning to no sparge 1st runnings, and just remash at 154 for 60 mins with new 7# of grain. New 7# of grain to contribute 34 pts. Am I off? How would you estimate 2nd runnings gravity with addition of new malts?