Bulova Accutron batteries

Hello all...my Accutron ran down while I was away, just really hate leaving it for any length of time in putting a new one in as l know they might not bother working again if left a long time.Anyway I had some Kodac AG3 alkaline batteries which equate to the 392 type.Obviously they take a 394 in their modern iteration and were apparently altered in circuitry as they used to take a 1.35 volt American battery years ago.So I stuck the AG3 in the watch with the plastic spacer , the battery is floating around in the gap inside it...thd odd thing is, its now keeping almost perfect time whereas with a 394 in it was 6 seconds slow a day.Clearly thd AG3/392 is smaller but the same voltage..so if just shouldn't last as long as its physically smaller, but in an emergency(if you could call it that!) then one of these will do.Ill buy a silver oxide battery when I get round to it