You can however, detect level of buff depending the ability itself
I'm pretty sure it is stated in Tooltips of the buff at unit's Status:
Level 1 XXX
This unit has XXX; its attack speed will increase bla bla bla
Check the level buff, it says from Level: 1, to Level: 4, so, it can differs
Learn the Ability, and type -test
And see the Buff Level
Type -reset
and learn the spell to next level
Type -test
And see current buff, level 4