Measurement of Forecast errors in APO DP

I am using APO DP version 5.

It is likely that I will need to use the BADI /SAPAPO/SDP_FCSTERR for a user specific measure of forecast error.

Does anyone have any experience of using this BADI?

For example if I want to have a user specific MAPE based on [absolute(actual minus forecast) / (forecast)] rather than the standard MAPE based on [absolute(actual minus forecast) / (actual)], could I use the BADI for this?

Thanks,

Bob Austin