James, has this worked for you?
Would be keen on brokers/others views on whether this actually works. I personally havent seen this - but it would be interesting if it holds.
I order valuations every day as part of my job. A colleague of mine used to order valuations and put in the previous valuation amount 5 years ago which was about $150k under the market value. Guess what the valuation came back at? You guessed it. The same price as 5 years ago! The customer put in a complaint, we rang the valuer and they upgraded their figure by $150k no kidding. This was not an isolated incidence, that colleague no longer works in this role
I don't think it happens every time you over quote but from my experience it does help to over estimate by about 10% or so.