As I already suggested, it's all about context, and what is required to be unambiguous. A primary feature that I noted was whether ἁμαρτία wa S or P - plural denoting real sins and so inferring "in (real) sins" whereas singular denoting the concept of sinning, and treated more abstractly unless a particular sin is in view.
Another aspect of context is the use of νεκροὺς: ὄντας ἡμᾶς νεκροὺς (we being dead Eph 2:5) is unambiguous re the following τοῖς παραπτώμασιν, versus λογίζεσθε ἑαυτοὺς εἶναι νεκροὺς (consider yourselves to be dead) in Rom, 6:11 being unambiguous as to being alive.
Where you have the concept of death through sinning (ἁμαρτία - sing.), a particle would be used (Rom 5:12).
JM really deserved a stiff rebuke. It's quite out of order to come in and accuse someone of lying as your first port of call, and without even faintly attempting to prove it. And moreover, why "lying?" Why not "mistaken?" Even had I been wrong, "lying" would conote an element of deliberate intent which JM also failed to prove and had no ability to do.
