You are correct! My ears can be quite sensitive to nuance and the whole of my ears and brain together can be quite discerning at times, for instance hearing distortion that my analyzer software has mistaken for background noise, or detecting a very slight shift in imaging that turns out to be a contact that needs to be cleaned or tightened down.
I consider myself a subjectivist that finds measurements useful. Measuring the placement of speakers very carefully can be quite handy as a starting point rather than just trying to eyeball them into position. If it still sounds off and you know the speakers are positioned very accurately and symmetrically, at least you know positioning is not the cause of the problem. Taking a near measurement sweep of one speaker and then the other and comparing them can tell a lot too. It may not reveal what the sweep should look like to sound subjectively best to you, but it's a pretty safe bet they should look very close to the same or the imaging will be off.