it is not exactly hours for the US engines, they are cycles. For some cases it will be more than 15 and for some it will be less than 2 (per hour). For ferry flights you won't use much cycles, for airshows and training you will use much more
He didn't say that it will be delivered to airforce serially with TF-35K, he said they will fly it in 2028+They aim to deliver 20 TF-X to Air force by 2028