This has not been mentioned for sometime, at least I have not seen it, so I will address it again.
First, mounting, what looks exactly like breeding, is common with all monitors in captivity and may or may not have anything to do with reproduction. Both sexes will mount members of anyother sex and will do this at any age.
Once a friend was here and looked in a cage of two day old ackies and yelled, holy crapola, those babies are mating. Yes, even at two days old.
Its seems to be an extreme attempt at positioning in a group. In nature or very large cages, only the slighest head movement is enough to comunicate to another individual and get a responce. But in confined quarters, they simply cannot get a correct responce. If one wants another to leave, it can't. Where is it going to go. So instead of whispering, get out of here, they now have to yell and scream. Get out of here.
Also, its not always, get out of here, but also, get off my basking area or get away from my food, or if I catch you next to my girl/boy friend. There are lots of reasons for this mounting behavior. The next level of this is, doing harm to the other. So please take it as a warning.
If indeed it was breeding, and the female is cycling(has viable ovum) then nesting and egg laying can happen as fast as 8 days, or, as long as never, depends of cage conditions.
I have a red ackie down now(nesting). Recently I have not been paying attention to my smaller monitors, but, last week I recieved eggs from my stripe necked ackies, today, if I am lucky, eggs from red ackies, and I have two yellow ackies gravid too. I guess feeding is important. Good luck with yours, FR