http://www.inven.co.kr/board/ro/1949/2396
It is, in fact, still 1 second at SkillLv 10. The cooldown formula was rescaled so that SkillLv 10 matches the old SkillLv 5 cooldown.
Note how after each cast, the RT icon is shadowed much darker than Trigger Happy Shot.
RT has a cooldown of 1s at SkillLv 10, and an after cast delay of 1s.
RT icon gets both, making it darker.
Trigger Happy Shot icon only get the after cast delay shadow.