The average life was 10 hours because pilots were treating the aircraft like a piston engine and flaming out the engines through too fast of acceleration. That cut the average life of the engines in service to less than half their rated 25 hour service life due to flame outs weakening the blades, which used a less heat resistant alloy than the original design. The frequency of flame outs due to pilot error forced them to add an aerial restart mechanism before realizing they needed to just add a restrictor to the throttle to prevent the flameouts in the first place.
Keep in mind that was the first model of Jumo 004B, later versions increased engine life substantially as did better training and the throttle restrictor. The models about to phase into production in 1945 when the war ended with rated for 50-100 hours life.
There is a good book on the various German wartime jet engine projects:
https://www.barnesandnoble.com/p/ge...MIwfuA64D05AIVaf7jBx0gBgTdEAQYAiABEgJmJPD_BwE