the calculation for reference stations is based on the next available base station.
So the times might not be 100% correct for reference stations and could be a couple minutes off from the actual high or low tide time. I haven't found any major problems with that so far and use reference stations myself.
But if you arrive at your spot and it's high tide instead of predicted low tide then maybe better not use reference stations
If people concentrated on the really important things in life, there'd be a shortage of fishing poles.