Stephen Farrell's comment

The comment is:

"[I]s the overlay-reliability-timer in the configuration defined in 11.1
supposed to override the "15 second" timer ("Maximum Request
Lifetime") defined in section 2 and and used in various
places, if the value of the overlay-reliability-timer is more
than 15000?"

I modified the definition to explain that the 15 second value is in fact
the overlay-reliability-timer value multiplied by the number of
transmission, 5.