This is what you get for relying on ANY meter. If the new meter recommended exposures 2 stops different than the old one, you should have noticed. If you didn't, then apparently you don't interpret your light meter's reading and just plug its recommendations in your camera. You should always take the reading your light meter gives you about as seriously as a politician's promise. It always needs interpretation.
I developed, as always, my films (Fomapan 100 in rodinal 1+25)...and the result was almost a disaster with the films underexposed, I'd say at least 2 stops.