As I see it there's possibly a contradiction between Abhidhamma and Sutta.
It is said in MN18:
Dependent on eye & forms, eye-consciousness arises. (...)
Dependent on ear & sounds, ear-consciousness arises. (...)
Dependent on nose & aromas, nose-consciousness arises. (...)
Dependent on tongue & flavors, tongue-consciousness arises. (...)
Dependent on body & tactile sensations, body-consciousness arises.
It is possible and everybody can verify it experiential, that there are forms, sounds and so on (sense-objects) and eye, ear and so on (senses) present in the same moment. Dependent on sense-objects and senses the respective consciousness arises. If there are eye and forms and ear and sounds at the same time, there arises (and have to be) eye-consciousness and ear-consciousness at the same time. Why should it be different?
Here attention (manasikāra) becomes very important, because it is "responsible for modification of the perspective" of an experience in a given moment. Manasikāra brings something out, to the foreground, while everything else becomes the background of the experience, which gives rise to kind of a perspective, which is part of the illusion of a subject to whom an object is present.
This is for example why Sobeh didn't see the hand of his friend.
Sobeh wrote:One time I was daydreaming and staring off into space, and didn't see when my friend was waving his hand in front of my face.
There was eye-consciousness depending on the eye and form (his friends hand), but because of manasikāra this was possibly put deeply into the background of the experience, which then didn't really come into the focus of perception.
This is completely in accordance with my own experience in opposition to what the Abhidhamma teachings say.
I couldn't find a sutta reference for what I say on manasikāra. My understanding developed out of the shorter notes on viññāna by Ven. Ñanavira Thera
and my examination on the subject in practice, so just my two cents...
best wishes, acinteyyo