for those not computer gifted:
"...STOCK SERVICE PISTOL DIVISION requirements and is NOT meant to be a definitive list of approved pistols.)
Astra A-75, A-100, Beretta 92FS, 92 Elite, 96, Cougar, Browning, BDA, CZ 75, 85, 100, Daewoo DP-51, DH-40, Desert Eagle Baby Eagle, EAA Witness, FEG PJK-9HP, Glock 19, 17, 20, 21, 22, 23, 26, 27, 29, 30, 31, 34, 35, H&K USP, Kahr K9, K40, Para-Ordnance LDA, Ruger, Ruger P89, KP89, KP90, KP93, KP94, P95, P97, Sig, Sig 220, 225, 226, 228 & 229, Smith and Wesson 908, 909, 910, 1006, 3913, 3953, 4506, 4516, 4566, 4586, 6904, 6906, 6946, 4013, 4053, 4046, 410, 4006, 4043, 5903, 5904, 5906, 5946 & Sigma, Smith & Wesson Performance Center Shorty 9, 40 & 45, model 5906 Tactical, Taurus PT92, PT908, PT99, PT100, PT940, PT101, PT945, PT911, Walther P88, P-99
NOTE: Selective DA/SA pistols MUST begin hammer down."
I count 8 models listed in this non-inclusive IDPA rulebook list that are or were available with a DA/SA trigger and no decocker. When this rule was written, the CZ pistols were not yet available with a decocker. The note at the bottom is the most telling item.
There is nothing in the rules about proper decocking technique.
9X45, have you ACTUALLY been to an IDPA match? You really need to read the rules if you want to compete safely.