This code has just been hammered to death on this forum in the past 2 weeks so please search for this 36 responses thread which addresses your question (search for "add on code 99459" to access this discussion). There will also be an article in the upcoming OB/GYN Coding Alert on this topic.
Except the information about 99459 is not totally accurate. The staff time was valued based on in-room chaperone time when the exam is taking place, not general staff time during the entire visit, and G0101 and Q0091 already account for practice expense (including staff time and pelvic exam pack) in their assigned relative values so the use of 99459 would not be appropriate due to this and the fact that neither of these HCPCS codes is a CPT E/M service as required under the only allowed primary codes stipulated in CPT.