I am thinking that the previous version of the rules (E4.3 which modified rule 45) told us that we could not release the boat during the time between one minute to the start and the start. We had to either launch or relaunch the boat before 1 minute to go before the start or hold the boat until the bell and then we could release it, but we could not give it a push, due to rule 42 and E4.3 (Propulsion) within 1 minute to go before the start. We could, however, give the boat a push any time before the one minute signal.
Now (through 2020) we can launch or relaunch the boat any time we want. Rule 45 is omitted by Rule E4.1. But I figure rule 42 and some other rule still tells us that we cannot give the boat a push inside of one minute to go before the start. I cannot find the rule that tells us that we are considered to be racing at one minute to go before the start.
I am not sure that everyone is on the same page with these rules. I hope I am somewhat correct in my perception of the past and current rules.
Scott