Looking at tbt - I think you should have dropped 19 and picked up 11 then instead of going up empire could have gone up pandora from durston - would have saved you some distance for sure maybe saved you a marginal bit of climb - mind u I dont think empire was as steep as Pandora from the east.
I think even if I'd done the same route but picked up 11 instead of 19 (so 16-17-15), I would have saved a few metres. I did think about it on the way but decided on 19 because it and I were both "there". Oh wait, I see what you mean now.
Going 17-13 via 8, which I'd already collected (thus dropping 15 instead and was something else I looked at), to pick up both 19 and 11 just didn't seem right. I considered dropping 8 earlier for later collection but also decided that'd force me into going 17-8-13 later when I thought I may need 15 and/or 14, but I could have picked up either or both of those between 13 and 12.