SAP is a running count of events weighted based on frequency in a regular shoe. I've seen that when the two to three counts are equal and the other two counts equalize that is not a NOR shoe, but an MDB+ shoe. But, if one or two of the counts are a lot higher than the other 2 or 3 counts then it favors a NOR shoe, which is basic. Typically, I play S40 by default when using SAP as it is the most forgiving system once you know the mode. The mode typically will be decided by the SAP count for the 3's and 4's. If 3's outnumber the 4's, 3 to 1 , then Mode 3 is used. If the 4's then mode 2. Now the shoes with the variations on these such as 3's and 4's being both high, typically are more difficult to play. This is where the 1's , 2's and 5+'s come into play. If your count for 2's are the lowest then in a shoe with a lot of 3's and 4's default to TB4L. Now, comes the hardest shoe type, I think. Having SAP counts where there are 2's, 3's and 4's. This is telling us that the best system should be OTB4L mode 3, but there are times were the ZZ come and then it can hurt you. Hope this helps out. Let me know if you've seen this.