Amount of cane sugar and dme off flavors

[CBMbrewer]

I am in the middle of brewing a double ipa and came up fairly short on my pre-boil gravity. I have usually gone with using 5% cane sugar with ipa's to boost the gravity without increasing the body and residual sweetness. With my recipe as is, 1lb would be 5.1% of the fermentables. But I would still be short of my desired og. Could I increase it to 10% without any cider-like off flavors or super thin body? I did not use any carapils or wheat in this recipe.
My other option would be to throw in some extra light dme. I could stick with my 1lb, 5% cane sugar and add 1lb, 5% extra light dme and that would get me to my desired gravity. I was never really too pleased with my partial mash batches and I am pretty sure it is the "extract twang" that many of us hate that I really don't like. Do you think having 5% of the fermentables as dme would impart any of that malt extract flavor?

 

[ncbrewer]

I used cane sugar as 10% of the fermentables for several batches when I was getting higher FG than I wanted - I felt that this kicked the ABV up and somewhat made up for the poor attenuation. I couldn't detect and cidery flavors. It didn't seem thin either, but the high FG might have been a factor.

 

[CBMbrewer]

How high was your fg when you used that much cane sugar? I mashed pretty low 149-150, so I should get pretty good attenuation.

 

[ncbrewer]

I was brewing with extract. Typical: OG 1.044 - FG 1.020 without the added sugar. With the sugar, FG stayed about the same.

This thread discusses adding sugar: https://www.homebrewtalk.com/f12/how-much-cane-sugar-safe-276529/

I've concluded sugar ferments out completely, so the beer is not thinned out when added in addition to the normal malt. If it replaces some of the malt, it thins it. (IMO)