At this point I'm reluctant to pass out the spreadsheet as the calculations are hidden all over the place and the spreadsheet is essentially held together with bailing wire and duct tape. One click in the wrong place and it could start giving bogus numbers or stop working all together.

For example there are over eighty cells with the following equations to systematically search for the W point and the 0.1 point:

=IF(H23=0, 0,(C23+(H23*($E$35-B23))))
=IF(AND(B23>=$E$35,B22<$E$35),(((C22-C23)/(B22-B23))),0)
=IF(AND(C25>=0.1,C26<0.1),(((C25-C26)/(B25-B26))),0)
=IF(K25=0,0,(B25-(C25-0.1)/(K25)))