I think you are right. Manner of living could refer to the way you choose to go about your daily life, without referring to what you own or material things. It's more of habits and things you do. Standard of living is more concerned with material things I think, like how expensive your house is, how you look, etc. I could be wrong, but that's what I think.

I agree with you. Standard of living has some statistical basis to it. Manner of living, I believe is more subjective. I believe you can use standard of living for both though. I met a woman in Mexico who had a fairly decent standard of living in Cozumel; however, longed for the days when she lived in the Yucatan and was very poor and described her daily life there with a lot of longing to go back to it. I thought afterward that for me, that would be an awful standard of living and for her, it was everything.