Hello! I also agree with mr. Sunil and mr. Asif.
From what I am understanding from the conversation, I think you do not have a tablet counting machine or your filling machine does not have a tablet counting tool. If this is the case, then huge efforts should be put in place to reduce the risk of having less tablets per bottle.
The control that you mentioned (manually counting tablets) can be very questionable since manually counting tablets leads to much error, even for small quantities; and the performance of that inspection would vary a lot from one person to another. It can be done, but a lot of effort should be put into Qualification and Validation to support it.
I strongly suggest to get a tablet counting machine; or at least, having an automitized equipment to do this process control as Mr. Asif suggests. I am affraid that getting a weight control machine could not give you enough resolution/presision to effectively identify bottles with 1 less/more tablet in it because the weight difference that 1 tablet represents, could be shadowed by the natural variation of the total net weight of the product.
I hope I explained myself clear and not introduced more confusion to this matter.
Warm regards!