Does PanF+ need a special treatment when used with flash?

With constant light conditions I get nice looking PanF negatives in rodinal 1+25, deep/rich blacks for the highlights and plenty of detail in the transparent parts of the negative.

With the same treatment, only now with flashed exposures the negatives seem a little to transparant with little contrast in them. At first glance the negs looked underdeveloped, but looking at the prints I am reluctant to go for longer development times since the contrast actually feels a bit higher than expected. (I went to a paper with less contrast and the darkroom exposure times are about 25%/30% shorter with the flashed pictures.) I also suspect I am loosing highlight detail.

Since I don't have this problem with other films (the late Kodak125PX, or FP4) I ask the, usually wiser than me, men of APUG if PanF+ needs a special treatment with the super short light bursts of a flash light?