It would seem logical (but perhaps incorrect) to assume that the row(s) you are inserting will always have ordered and consecutive OID values relative to any existing OID values in the table. So, if inserting rows into an empty table, logically your fist inserted row would be OID = 1 (OID = 0 if a shapefile/dbf). Similarly, if inserting rows into a table with existing records (last existing one ending in OID = 222), then your first inserted row would be OID = 223. Note that the insertcursor method does not have a sort order parameter, so no chance for that messing with an otherwise orderly universe. So maybe a faster/better work around would be prior to running an insert cursor, run a searchcursor to grab the largest existing OID value, and in your insertcursor, start counting at that number.