I thought I would pitch in a thought real quick...
I agree with James - using a UW strobe topside results in a lot of heat. From a purely physics standpoint, water dissipates heat MUCH faster than air and using your strobe topside could very quickly destroy your strobe and possibly even result in someone getting hurt.
Theoretically, a chemical change could happen within the strobe, causing a pressure change to great for your cover to withstand - resulting in your battery cover (or the strobe itself) to "give" and release the internal pressure of the strobe.
In fact, I seem to recall Sea&Sea had to recall a lot of YS50s because something in the battery cover was not designed properly, causing a few serious accidents when the cover forcefully popped off the back of the strobe. In what case I remember a diver got hit in the head underwater.
And it appears as though you are saying this particular strobe was flooded and you didn't send it in for repair - even if the strobe works
there could be (and probably is) some level of internal damage. That seems problematic to me, at best.
To be more direct - if it were me, I dont think I would use a UW strobe (previously flooded or not) topside as a replacement for a hot-shoe mounted flash for regular shooting.