yes you can say 1 activity per day is the limit, but it's 14 activity per 2 weeks more precisely
and if you didn't max out the biweekly activity count, you will have potential activity saved
for example the first biweekly you posted 3, then second biweekly you posted 3 more
you will have 6 activity total but potential up to 28 points
so by the end of third biweekly if you have more than 14 posts all will be counted for
for example you made 30 new posts, you will then have 36 activity total