I have to agree with Ralph Lamabrecht and Michael R 1974. Change nothing in film development and then print them well.

I make your "mistake" all the time, since I rate my 400 speed film at 200 and place the shadows on Zone IV. Ansel Adams would therefore say that I'm shooting it at 100. Indeed, when I take incident meter readings that's the ISO I use.

All the photographs on this Tumblr blog page were exposed in this manner. The first one contains only 2 zones of contrast, the last one about 12 zones. So in the final analysis not even the tonal range makes that much difference when it comes to exposure.

There are only two ways to make a two stop exposure mistake. You picked the right one.