not sure how relevant his is however but c3 is a weekly total that references
the previous weeks total and the current weeks totals as well and of course
is the cell I want to =0, the effected cell needs to be b1 as any shortage
for the week in outgoing bills need to come from the savings entry,
transversely all excess funds need to go into b1 hence b1 needs to adjust
itself to ensure that c1 remains =0