flash the memory? for speedometer correction?

I bought a repo 09 taco and have determined that the speedometer reads near 10% high. the odometer reads about 3.7% high and the tach reads about 30% low. It has stock size tires on it. I took it to a shop today and had it plugged into a diagnostic for a couple mile drive around. The diagnostic box verified that it was off close to what I calculated on the speedometer and odometer. The shop mechanic recommended that I take it and have the brain flashed at a shop he recommended for about $100. Anybody had a similar problem or have any ideas for a fix? It doesn't make sense to me to flash the memory if it reads correctly on a attached computer. Seems like it would be the cluster to me. Looking for advice.

Thanks

 

He described it as though it would reprogram everything.

Do you think it could be the cluster?

 

It could have a hypertech calibrator installed, if so it would be behind the gauge cluster. I installed one so that my speedo would read more accurately after I installed larger tires.

 

I just got a PreRunner SR5 '06 model and the speedometer is reading like 60 when I am doing more like 70. 35 when I am doing more like 45. I can't go very slow in first either slowest on flat terrain the speedometer reads 4 or so mph, that isn't very slow. It seems to have way high gears, or the tires are too large. Can't figure it out. 89k miles.

Anyone have same probs or know how to fix this. I am going to ask the dealer but any input is greatly appreciated. The tires are factory specs 265/70-16's

Thanks,
Bob