Secure Net Bpp revision kit question number 203 page number 55

Hi My Dear tutor, I have a question

My calculation for planning and operational variences in material price and usage is are different from the answer

My calculation

Material price planning variance

Actual quantity used at revised rate-14280
(100000*0.035*(4$*1,02)
actual quantity used at standard rate-14000
(100000*0.035*4$)

equal 280A

Material price operational variance

Actual quantity used at actual rate-18375
(100000*0.035*5.25$)
Actual quantity used at revised rate-14280

equal 4095A

Material usage planning variance

Revised usage———————-4200
(100000*(0.04*1.05)
Standard usage based on actual production
(100000*0.040)———————4000
equal 200*4$===800A

Material usage operational variance

Actual usage———3500
(100000*0.035)
Revised usage—-4200

equal========700A*4$=2800A

Why Material usage operational variance multiplied with revised standard cost of 4.80$ not multiplied with 4$?

Besides material usage planning variance the rest remaining three calculation method is different from mine?is my calculation considered to be correct?is bpp’s calculation methoed based on old method?

Could you explain it please?

thanks in advance