Before anyone freaks out...I've got nothin' against imputation. I'm all about imputation. What I don't understand is why Paul writes the way he does about the subject of imputation. Or better stated even more, why does he use the word in such a confusing way?
Perhaps you don't think it is confusing. That's probably because your English Bible isn't translating the Greek word λογίζομαι as "imputed". It some places it certainly would add undue confusion. But in others it is quite helpful. Take for instance Romans 2:26. I don't see a single popular Bible translation utilizing the word "impute". Perhaps its just me but reading this verse properly answers many questions. It also asks a couple others.
How could we ever consider imputation as something that is "infused" into us? The usage here in direct context to justification and the validation of Gentiles makes it obvious that this is not the case. Paul is not saying the circumcision is somehow made manifest in a material and concrete way. Instead this is a statement of God's decreeing. This is God pronouncing "I am your God". This of course is spoken in the sense of covenant (Gen 17:7-8) and eschaton (Rev 21:3). No one will hear this deceleration at the inauguration of the eschaton without having heard it by joining together with Christ in the New Covenant.
In what sense is Paul using this language? It really isn't fair to bring our theological standards to bear on this question without context. And it really isn't a question of strictly either/or. It's more like a both/only-one type of question. It is either an all encompassing deceleration or it is solely a here-and-now deceleration. There certainly is some room for thinking this is some type of eschatological "judging" (Rom 2:27) but that is really stretching it.