Conversion at 5.2PH?

Does any know if conversion with this grain bill will be affected. For some unknown reason my PH was lower than i expected 5.22PH. Should have been 5.5 per my spreadsheet. My preboil gravity was suppose to be 1.046 but was 1.042 i mashed for 75 min. I normally am within a few points. Anyway, would love some feedback on if this type of grain bill which i believe has a higher percent of low enzymatic malts has difficulty converting because of a lower than optimal mash PH.

74.43 Marris otter
7.88 munich 10L
2.01 chocolate
3.92 victory
3.92 C-120
7.84 C-40

75% brewhouse efficiency

I can’t imagine why there’d be any problem.

I made my last Saison at right ~ 5.25 pH, after reading a posting (by Martin I think) that such a pH could actually be beneficial to the style, as it is a beer where a slight tartness can be desireable.  I was within a point of my target gravity, and the beer attenuated all the way down to 1.002. So I think I converted plenty of sugars there.

How did you measure pH, and at what temperature?

Milwaukee 101 PH meter calibrated at 77F.

There should be no problem with conversion. If anything, the low pH may promote excessive conversion and produce a bit thinner beer.  It will still be beer though!