There is a WORSE factor to resuming saves.
I am in the practice of saving before I approach convoys. I don't do an incremental save, just the one from a number of miles out so I have to make another run if I get canned. And Very Hard difficulty has some pretty decent Japanese captains! Or at least, rather accurate men manning the depth charges.
The problem with resuming saves is that it must reset AI somehow. I noticed on one that I had approached on the surface and traveled far on ahead before going to periscope level and stopping to wait for the convoy to come to me. But when I loaded the save... mind you, bad weather, past dusk and a good ways off... as soon as it loaded I had the nearest destroyer INSTANTLY firing on me. I had another save where this problem repeated, but where I did not get fired on. In that one I simply had them all become instantly aware of me and go into swarm mode overhead.
Not fun.
