What can I do to improve speed in this case?

I have a fairly modest model using Solver.  I have a number of almost identical worksheets that need to be updated via download.  It's a lot more convenient for me to put all the worksheets together for the update - but they are NOT connected to each other by formulas, references, etc.  (well, except for a summary sheet that grabs some of the data from each .. but is NOT involved in the individual sheet Solver work.

When I set this up as individual sheets, Solver works "fast enough".   But, when I bring all the sheets together, even the "Setting up Problem" takes a lot longer for each one .. doing them individually, one at a time - NOT somehow combined.

Any suggestions?  Might this be a bug?