Double infusion vs yeast attenuation

[Oude Brouwer]

Good Day to all.
I wonder if double infusion or decoctions during mashing process may have an influence in yeast attenuation.
Does the conversion of more complex sugars may affect the capacity of the yeast for ethanol production?
Are there any risk for the yeast to generate of non desired substances due to these mashing methods?

Thank you!

 

[Iseneye]

I take it the question is - does step mashing affect wort fermentability and attenuation? If you step mash over different alpha and beta temps then you get a different wort than a single rest.