These are, of course, only estimations. If you mainly do high reps in your workout, you'll get better at that, but your 1-3RM won't be that high. In other words, you would possibly be able to do 12 reps with 75-80% of 1RM.
On the other hand, it is quite common that when focusing on low reps, your low rep RMs increase, but your ability to do higher reps decreases ie. just 8 reps at 70%.