Pagespeed is designed to provide some guidelines to let you know what can be done to reduce your page load time, which actually means that you don't have to stick to them to raise a better result position.
Said that, Google is introducing some guidelines in what mobile platform means by saying what web is able to be rendered fine on their devices and what not.
Having a great page load but a poor UX implemented on your site can mean having a site not compatible with mobile devices and that might mean a downgrade on search results coming from mobile so, again, PSI won't raise or decrease your site position in a speed optimization basis.
You're just mixing different tools and functions.
Kind regards.