Resets only reset the CLONE bonus, so what you lost in AT was all the clone bonus you had. You need to hover over the AT stat in the digi window to see what is your Base AT, and what was your clone bonus. So of course it's gonna be weakened now, you just lost all the bonus you had, and that bonus generally adds 70-99% (80 being the average) more to your AT.
Now if you start over again and bring its AT up to 12 again, whether you get better or worse stats depends on if you max or get the minimum for each stage. That's where resets help, mostly in the early stages of cloning. If you get below the middle range of a clone, for ex. the range is 13~19, and you get 15, use a reset (regular) and try again to hopefully get 17+. Repeat this until you've gotten at least above average for each stage up to stage 6. After 6 you can just fail on purpose instead of using an expensive reset. The lvl of your digi has nothing to do with the clone bonus.
IGN: ProjectWAR / GDMO
Kunemon lv41 5/5 (127%) *NEW*
Raptordramon lv73 5/5 (127%)
Draco Blue lv61 5/5 (127%)
Shamanmon lv55 5/5 (127%)
Dracmon lv52 5/5 (126%)
Biyomon lv84 5/5 (126%)
Elecmon lv89 5/5 (126%)
Mekanorimon lv80 5/5 (125%)
Commandramon lv61 4/5 (120%)
Ryudamon lv74 4/5 (120%)
Musyamon lv81 4/5 (119%)
Draco Green lv82 4/5 (119%)