I have attached my current formulas used and work through to better provide insight.
Grade I Fixed Cost (+) Grade II Fixed Cost (+) Common Fixed Cost
$225,000 (+) $70,000 = $295,000
Contribution Margin Grade I = Unit Price - Unit Variable Cost
$3,400 (-) $2,686 = $714
Contribution Margin Grade II = Unit Price - Unit Variable Cost
$1,600 (-) $1,328 = $272
Weighted Average Contr. Margin = Contr. of Grade I (x) .5 (+) Contr. of Grade II (x) .5
520 (x) .5 = Grade I 260 (x) $3,400 = $884,000
520 (x) .5 = Grade II 260 (x) $1,600 = $416,000
1,300,000 / (3400+1600) 5000 = 260
New Break Even Point = New Fixed Cost/ New Weighted Average Contr. Margin
$295,000 (/) $520 = 567
Current Op. Income = Contr. Grade I (+) Contr. Grade II (-) Fixed Costs
Operating Income
New Sales Volume (*) New Weighted Average Contr. Margin - New Common Fixed Costs
$2,080,000 (*) $493 - $105,000 = $1,025,440 - 70,000 = 955,440
Break Even Total Units = Total Fixed Cost/Weighted Average Contr. Margin
$295,000 (/) $1134 = 260
Break Even Units Grade I
520 (x) .5 = 260
Break Even Units Grade II
520 (x) .5 = 260
Change in CM = 260*(3400-714)+260(1600-272)