I don't think so. It'd be nice, but the issue is very complex.
What you're doing is essentially making your own extract that you will then rehydrate with more wort. Yet, the "sugar" contribution is zero because you've already accounted for that in the grain bill.
In your recipe, you can account for this with an ingredient line item. What you can create is a grain ingredient that contributes only color, not gravity. This would account for your color shift, while not changing your anticipated gravity.
I played around with it and came up with this off the cuff ingredient I called "Maillard's Touch." It changed color, but did not seem to effect gravity or efficiency calculations when I tried it as high as 20% of a grist.
A quart is about 2 lbs, so I used that as a model and that changed a 6.5 SRM to about 21. It's a WAG on my part, but fits what I think should happen.
With a little experience, you can hone the color to exactly what you experience by just changing the ingredient color.