Het is only for recessive genes not showing the morph and neither of these are recessive. Also butters and lessers are the same morph to most people, if not they are very similar and compatible for bels.
Here is what world of balls says about that pairing.
12.5%|1/8|Normal
12.5%|1/8|Lesser
12.5%|1/8|Spider
12.5%|1/8|Lesser Bee
12.5%|1/8|Butter
12.5%|1/8|Butter Lesser
12.5%|1/8|Butter Bee
12.5%|1/8|Butter Lesser