I'm not really sure how or why this works, but if I shift into forms slowed, I end up with a lower "natural" hitroll than if I do hasted.

(981hp 1015m 660mv civilized) sc stats
Str : 17(20) Int : 23(23) Wis : 20(20)
Dex : 18(15) Con : 4 (9 ) Chr : 20(20)

(981hp 1015m 660mv civilized) shape bull
You flicker and blur into the shape of a raging bull.
You maintain your speed as you shapeshift.
You maintain your levitation as you shapeshift.

(981hp 999m 660mv civilized) sc combat
rev
Hit Point: 981 /981 Mana : 999 /1015 Move : 660 /673
Wimpy : 200 hp Hitroll : 28(25 ) Damroll : 29(36 )

(981hp 999m 660mv civilized) You concentrate a moment and return to your normal shape.
You maintain your speed as you shapeshift.
You maintain your levitation as you shapeshift.

(981hp 993m 660mv civilized) c haste
You start moving at normal speed again.

(981hp 963m 660mv civilized) sc stats
Str : 17(20) Int : 23(23) Wis : 20(20)
Dex : 18(19) Con : 4 (9 ) Chr : 20(20)

(981hp 963m 660mv civilized) shape bull
You flicker and blur into the shape of a raging bull.
You maintain your levitation as you shapeshift.

(981hp 906m 673mv wilderness) sc combat
Hit Point: 981 /981 Mana : 906 /1015 Move : 673 /673
Wimpy : 200 hp Hitroll : 28(25 ) Damroll : 29(36 )

(981hp 906m 673mv wilderness) shape snow b
You flicker and blur into the shape of a snow badger.
You maintain your speed as you shapeshift.
You maintain your levitation as you shapeshift.

(981hp 890m 673mv wilderness) sc combat
Hit Point: 981 /981 Mana : 890 /1015 Move : 673 /673
Wimpy : 200 hp Hitroll : 35(32 ) Damroll : 52(59 )

(981hp 890m 673mv wilderness) enliven h
You start moving at normal speed again.

(981hp 875m 673mv wilderness) sc combat
Hit Point: 981 /981 Mana : 842 /1015 Move : 673 /673
Wimpy : 200 hp Hitroll : 36(39 ) Damroll : 52(59 )

(981hp 842m 673mv wilderness) sc stats
Str : 22(22) Int : 18(18) Wis : 18(18)
Dex : 16(16) Con : 21(21) Chr : 18(18)

(981hp 842m 673mv wilderness) enliven slow
You feel yourself moving more slowly.

(981hp 827m 673mv wilderness) sc combat
Hit Point: 981 /981 Mana : 827 /1015 Move : 673 /673
Wimpy : 200 hp Hitroll : 35(32 ) Damroll : 52(59 )

Your dex affects your hitroll.

Slow affects your dex.

Sorry, I didn't include the fact that the "natural" stats don't change for dex, but the "natural" hitroll does. Then the modified stats kick in, and you get a modified drop to hitroll as well.