MRP Recommendations

Hi All.

I have a question regarding the MRP and its reccomendation.

Our consultant at that customer also tested it.

When you run the MRP, eg from 20 may 2011 - 30 June 2011, the MRP gives about 500 recommendations.

Then when he back dates it.... eg... from 29 april 2011 - 30 June 2011...he gets about half of that recommendations...round about 250.

He gets a higher number of recommendations when he runs the MRP for a month then when he runs it for 2 months,

Is there anything on the production that we need to check for?

Thank you in advance.

Regards,

Jerusha