I've never heard of a "130ft rule" in realation ot Nitrox, nor a 40m rule for that matter (130ft = approx. 40m; 1m= 3.3ft)
What does scome to mind is that we were taught to limit the partial pressure (<= "pp") of Oxygen (<= "O2") to 1.4. Even in trimix training we were taught to limit O2 pp to 1.4 at all depths below 21m - the likely consequences of an O2 hit at depth are just too severe.
Don't wish to debate higher O2 pps just now. The question was about a 130ft rule:
It occurred to me that most people seem to buy their Nitrox mixes and the lightest mix available for sale seems to be EAN28. This would give a max depth of about 130ft when using the 1.4 max pp of O2.
1.4 max ppO2 / 5 bar total pressure = .28 % O2
With this explanation the officer meant that Nitrox is for max depth 130 ft.
He's assuming the lightest O2 % available is 28% and that max acceptable ppO2 is 1.4. Or whoever taught him the rule was making these assumptions.