In the days when I ran with detergents and heat, like Mark, I too was always repairing my solution hoses. I had 100 then later 135psi.
My conclusion was that the 300psi rating must be with cold water and that when running hot, the 300psi rating came tumbling down and hose bursts were a common occurance. When I changed to 3000psi T/M hose, the problem disappeared.
Spend a few more pounds today for T/M hose and save buckets of cash, and the embarrasement of breakdowns, in the future. It's safer too.
Safe and happy cleaning
The Ken