Does single-file feeding mean the counter has only one track?
No. Several parallel vibratory tracks can each present products in a single file. Singulation concerns how individual tablets or capsules are presented within a stream, not the total number of parallel paths.
It also differs from lining up bottles on a conveyor. The objects and receiving stages are different. A line layout should distinguish product presentation before counting from container presentation before filling.
Does a separated stream establish that every piece was counted?
Separation prepares products for detection; it does not itself supply an independently checked count. Presentation at the feeder, sensing at the detector and contents in a completed bottle are different observation points.
Describe spacing and obscuration at the sensing region, with the product orientation and condition. A view of separated products farther upstream may not represent what reaches the detector.