I just won a DIII league with two guards at around 15k salary...and both of them had 12+ OD at the beginning of the season and have been trained in it to higher levels during the season...so the statement that an 18k SG has "probably 10 OD at best" is not reliable. It is certainly possible that the level is somewhat low on those two guards, but salary can be very deceiving.
http://www.youtube.com/watch?v=oHg5SJYRHA0