I think "M A" may stand for Maître Auxiliare, ie Uncertified Teacher. Also if the cards you were doing were 1921/22 then 1901 is likely to be the stamp for birth year. At age 21 it would have been the first time these people could vote and it seems they may have stamped up a load of cards for use and amendment with full date of birth later. I haven't seen any election years stamped other than at the top of the card or those with 1910 when they are stamped at the bottom of the card as part of the Commune and Département.