Extending a period for a foul--NF

[Bill D]

For many years, Rule 3-3-3 (or its predecessor) has stated:

"A period must be extended by an untimed down if during the last timed down, one of the following occurs:
a. There was a foul, other than unsportsmanlike or non player, by either team and the penalty is accepted."

The current version of 3-3-3 has deleted the words "last timed down" and replaced it with "last down of the period".

Is this a change or more sloppy NF editing?