Well - if you think about it - for one single treatment of each...

Well - if you think about it - for one single treatment of each - using oil for the flush - you are even at 40%. But then with IVF you may get twins or triplets - so are these cases really a success.
2% is apparently the normal rate of multiple births (without IVF), but with IVF it is about 20%, or 18% more. So taking this into account, IVF success could be regarded as significantly lower after one treatment, maybe only 33% versus 40% for the flush once normalised.

Not sure of the source for this article - but it is well known that IVF raises the risk of multiples.

https://www.babycenter.com/0_your-likelihood-of-having-twins-or-more_3575.bc

Excuse me for being pedantic - I'm just all over the topic, and there are a lot of vested interests keen to muddy the waters.