Graded Region Regrading Entire Site?

[formarch.70565]

I created a semi-complicated topo in the existing phase and need to grade a small portion. As soon as its "selected" to be regraded the whole site is completely simplified and I'm wondering if there is a way to maintain its original detail. The final goal is to create a grading plan with calculated cut and fill.

[formarch.70565]

I used copy internal points to maintain the level of detail and deleted points within the graded region so the grading plan is looking good except that the calculated cut and fill isn't quite right yet. It appears revit makes a copy of the origional topo that can be edited to create the graded region but somehow it doesn't calculate the cut and fill between the existing phase and new phase. My new phase indicates a huge amount of fill that seems to represent the whole site and not just my graded portion. Is this a three phase operation from existing phase (no cut and fill calc'ed) 2nd phase (no cut and fill but edited) and a 3rd phase that calcs the cut and fill between phase 2 and 3?

Thanks for your help?