Fuel tanks don't interchange

I'm a hybrid rebuilder, and have just run across something interesting.
(I've been rebuilding Prius's the last few of years, ....have rebuilt other cars for many years.)

There's been lot's of discussion here about filling tanks and not getting tank full, etc, etc. It appears Toyota has been doing some modifying in order to solve some of those issues.

I have an 08 that is about finished rebuilding.....replaced rear quarter panel, rear axle, rear bumper, and a few other small parts.

Without going into details...the fuel gauge would only blink. .....At some point before I got the car, the gas tank was partially collapsed (bottom). So after investigation, I decided to change out the gas tank, assuming something must have happened to the sensors in the tank.
I bought a used tank out of a 2005 Prius...(the salvage yard said their info said all 04 to 09 were the same).........well they're not.

The 05 electrical connections, fuel lines (there are several), and the 08's connections (more of them too) are somewhat different. The actual metal outer shell is slightly different also.
I don't know what year Toyota changed the tanks exactly. (or if they changed it more than once)

I got yet, another gas tank, this time an 08.....put it in.... and walla....the gas gauge now works correctly.

So Toyota has made some (untold about) changes trying to fix the tank filling issues.

So far I've rebuilt (body damage) on an 02, 04, 06, 07, 08 (2), and have a another 07 coming. (I'm looking for an 2010 for my self to drive) To say the least I've learned a lot about the Prius.

Hope this is helpful.