Parenthesis mistake for _notify_send period calculation

It seems there's a mistake in

function _notify_send() {
  $period = variable_get('notify_send_last', time() - variable_get('notify_send', 86400));

The code seems to work, but as far as I know, there's a parenthesis missing behind time(), and there's a superfluous one at the end. I believe the code should be:

function _notify_send() {
  $period = variable_get('notify_send_last', time()) - variable_get('notify_send', 86400);

Or am I wrong?
Anyhow I do not understand how the present code could possibly work, but it does !??

Note 1: this code is the same no matter which version (4.7 or 5)
Note 2: I've reworked the code to allow for html mails. If anyone's interested, let me know!