[Beery]

There are only two consecutive months where the game can issue the same AM14 patrol grid. It happens in July and August 1944. As for AM19, there are a couple of instances where AM19 assignments are a couple of months apart, so that in 1st Flotilla if you go out on patrol in January 1942, then if the next patrol is in April, you could get the same patrol grid. The same thing happens in April and July 1944, again in 1st Flotilla. Same in January and April '42 in 7th Flotilla.

One thing is for sure, if you have days spent in base set to 1 (or a very low number) and you go out on patrol on the first of the month, then come back on the 14th, then go on patrol again and return on the 28th, you will have a very good chance of getting the exact same patrol grid three times in a row.