Page 28, 2017 PADI IM, General Standards and Procedures, page 28:And if the shop says two days for OW, then the instructor has to do it. Why bother with agencies and standards?
9. Conduct no more than three open water training dives in a single day, night or combination thereof.
You can do per agency standards, "resort style" which is either pool in the morning (yes, all CW dives in one session) and 1 OW dive in the afternoon, and 3 OW dives the next day.
This isn't a violation. I'm sure I can dig into SSI and SDI standards for similar language.
But why bother with agencies? As divers need a card to go diving with charters or to rent tanks/get tank fills.