We see that, in the retrospective DOP, all deltas on fixed grades, intermediate stocks, and crude run have been eliminated. The deltas between actual production and retro DOP remain only in balancing grades and refinery loss (actual refinery losses minus retro DOP losses). In the allocation procedure, loss is treated as a balancing-grade product.

The balancing-grade deltas (actual production minus retro production) are allocated by following procedure:

1. The retro DOP of the participants is expressed in balancing-grade equivalents using product equivalencies.

2. The total delta (actual production minus retro DOP) for each balancing grade and loss is determined. The sum of these deltas must equal zero.

3. Next, the deltas are allocated to participants in proportion to their respective shares of production of that product in the combined retro DOP (expressed in balancing grades).

4. By the nature of this calculation, the sum of each participant s delta allocation will not be balanced between the participants but equal in amount and of opposite plus and minus signs, since the sum of such imbalances must equal zero. Accordingly, a further step is required to eliminate these imbalances. This is done by reverse allocation, as described next.