Keep in mind that the number of valid checksums with different combinations are an estimate because we are talking about collision and it can technically be between 0 collisions and maximum possible ones meaning 2048 with 1 missing word.
Probabilistically we say with 1 missing in 24 words there can be 8 valid combinations on average.
Example:
Only 5 are valid here:
goddess crane order member daring title renew autumn drive * sword slim lesson home focus flee silent dash shock adapt success laundry physical base
While there are 9 valid combinations here:
goddess crane order member daring title renew autumn drive rally sword slim lesson home focus flee silent dash shock adapt success laundry * base
And 13 here:
* crane order member daring title renew autumn drive rally sword slim lesson home focus flee silent dash shock adapt success laundry physical base
With 12 words:
135:
lava reason future wonder image hard hunt step basket frost * poet
130:
lava reason future * image hard hunt step basket frost invite poet
128
* reason future wonder image hard hunt step basket frost invite poet