The wizzwheel gave me an outward groundspeed of 117 and a homeward of 135.

 

Then PET = (tot.dist.x home g/s)/(out gs + home gs)

= (285 x 135) / (117 + 135)

= 152.7 (i.e. 153)

 

Working looks good - two points to add:

 

- accurate wiz wheel work .... and if you start with TRACK, you MUST apply DRIFT before you read G/S, I agree with G/S out=117kts, G/S home = 135 Kts

- PET formula ....Dist to PET = (D x H)/ (O + H) ... get the right numbers in the right place!!