Difference Between Two Records

[customaware]

I have a BO called MyData with attributes for Easting and Northing.

Imagine the data looking like

ID Easting Northing
1 1,000 12,345
2 1,101 12,456
3 1,342 12,342
4 1,355 12,411
5 1,378 12,503
6 1,402 12,475

I have another temporary BO called Delta which has two attributes,
Dx and Dy

I need to loop thru MyData and for each record, I need to get the difference in Easting (Dx) and the difference in Northing (Dy) between the two records. The record to compare must always be the one immediately preceeding the current record by ID.

I am trying to do this in a Process with a FIND ALL MyData ORDER BY MyData.ID ASC but then get stuck in trying to also get the preceeding record.

Can someone please advise if what I am trying to do is possible and if so, how?

Cheers,
Mark