Is There a Difference in Circumcision?

There's some suggestion that circumcision happened right before marriage. Maybe the midianite form of on happened at a later date. And perhaps they did it a different way. But what's happening here? Why didn't moses circumcise gersham? Already sent jewish tradition and and possibilities of midianite circumcision being different, i wonder if part of it was he spent his formative years in egypt as the odd man out.