Yes this is true and must affect their ability to be thorough. The crazy thing is because of their system of trying to save time on visits and repeat visits end up actually spending more time and money in the long run. If they had spent more time diagnosing and finding the isolation valve leak they wouldn't have replaced a heat exchanger! Perhaps Bosch should allow their engineers more time on a job (a stitch in time saves nine). I did find though all the Bosch men that arrived in pairs spent a lot of the time chatting between themselves about personal stuff, rather than fully concentrating on the job.