On my Honeymoon cruise (1994 on another cruise line) we got to San Juan at a regular time like any other port.
If you cruised from Florida and San Juan was your first stop, then you had two at-sea days enroute, and not a day and a half. It isn't a company line - it is the simple fact that 900 nautical miles takes time to traverse. Ships are faster now than they were in 1994 too. Most modern ships can cruise at 20 to 23 knots. In 1994 the common speed was 18 to 19 knots.