It can't be zero, that's impossible.
Try zero, and then go to advanced, and go to device log. Here is what we are looking for:
:e:6221
0,4915,4792,892,1579,893,1578,889,1582,893,741,918,1548,893,1579,892,1579,893,4374,864,769,888,746,866,767,919,719,888,741,892,741,893,1578,1727,1581,891,771,867,766,863
:e:24
0,4938,4792,837,1657,841,1631,841,1630,810,824,841,1630,863,1631,814,1657,836,4401,841,793,815,823,837,797,837,797,836,798,836,797,841,1657,1674,1631,837,797,841,794,815
The :e:24 stands for 24ms since the last pulse train. The :e:6221 stands for 6,221 seconds since the last pulse train ( button press).
You want to get that 24ms up to 75, and you're good. Keep playing with the number, checking the Flirc gui, and keep me posted.