I have a simple Solver problem set up to analyze a price increase. I have
about 20 rows that represent product groups (actually procedures - I work for
a hospital but I'll stick to general terms). These are broke down into three
columns and multiplied by a factor to get net increase in revenue - my target
cell. I have two constraints: a cell representing 10% total average
increase, and a range of cells representing the increase for each product
group to be between -20% and +20%. Specifically, my Constraint box looks
like this:
$A$12:$A$29<=0.2
$A$12:$A$29=-0.2
$AI$<=$AJ$9
AJ9 has a value of 0.10
All this works, and I believe is pretty simple as far as models go.

My question is I get different answers. Once I set up and hit "go" I get an
answer, with cells A12:A29 having values between 0% and 19% But if I erase
and set the range of cells to be 2%, and then rerun Solver, I get different
results.

My problem is simple enough that I can take Solver and tweak to get my goal.
But I am wondering if I am missing something? - I've seen increadibly more
complicated examples on this site.

thanks