High water pressure-spanaway water

Hello,
I'm having a problem that I hope some of you will help me with. Without our knowledge our water company (Spanaway Water, a non profit, customer owned, self governed company) came out and changed our water meter. That night our faucets started spitting sometimes when turned on. 2 days later we had a burst pipe in our bedroom where the line comes into the house. It didn't burst on a seem or a weld but in the middle of the pipe. Long story short Plumber found water pressure over 90psi. Water came out so hard it popped the shower nozzle off the wall. The reason we had the nozzle anyway was due to low water pressure. High pressure has never been a problem here.
For several days we noted high pressure in 80s and 90s. Our neighbor also had high pressures.
SW swears this cannot be, their system won generate pressure over 65-70 psi so it must be our water heater. PSE came out and checked the water heater after hearing what happened and pronounced it fine. SW insists still it is the water heater and that they cannot and are not to blame.
Now though, our pressures are 68 psi, morning, noon and night. Always the same 68psi.
Any thoughts about what is going on and who might be at fault? Are there any state regs on notification of changes to system?
Thanks in advance,
Diane

My guess is that the new meter has a backflow prevention valve. This creates what is called a closed system. What that means is, when the water heater kicks on the pressure increases and expands. Without a backflow prevention valve, this expansion is absorbed by the water main. With the preventer, this expansion has no place to go and the pressure rises in your house system. The cure is quite simple. Install an expansion tank in the cold water line before it reaches the water heater. It's a fairly easy DIY project if you can sweat a joint. Expansion tanks are less than $50. A pressure regulator valve will cause exactly the same close system problem. While you are installing the expansion tank, an inexpensive pressure gauge can be installed so you know for certain what you incoming pressure is. The expansion tank is air charged to the same pressure as the water pressure. This is done with a small hand pump or very carefully with an air compressor. It's exactly the same as airing up a tire.

An expansion tank may be called for here, but there is another, probably more serious problem. If the pressure got so high it split a pipe (not a a joint which could have been a bad solder joint), and the hot water heater didn't vent through the T&P valve, if it ever malfunctioned, it could blow up. My unprofessional opinion.

We already have an expansion tank in place which was checked by PSE and found to be working properly. It's a mystery. The meter they installed is made by Master Meter model AMR Dialog 3G RF. It does have backflow protection. Does it make a difference that the water heater had been off for about 6 hours when the water pressure read 90psi?
Diane