If our devs had used the patient ID value as the identity, it would have been a (10,10) seed. The way the current billing application handles patient IDs is increments of 10, then if it's a family practice, family members get added using the base +1. So wife (primary policy holder) might be patid 1270, the husband (on the wifes policy) would be 1271, and the three kids would be 1272-1274.

Luckily, we've never run into anyone who would use all 10 values...