It is an option to wait until he sues you. He may do so, or he may not bother, particularly if you offer to pay him what you think is a reasonable amount. You can send him a payment of $x dollars, saying that he can only cash the cheque if it is on the condition that he accepts this in full and final satisfaction of any account. You can also send that on a "without prejudice" basis, so that if there is a lawsuit, he cannot point to your proposed payment as evidence against you.

Offers of settlement can be made "without prejudice" so that they remain confidential and not used in evidence, as this helps to promote parties to try and reach a settlement without trial.

If he does sue you, it can be a defence perhaps that the bill included work that you did not authorize. If you do not make a formal assessment to him, you should at least send a letter, keeping a copy for yourself, putting him on notice about your concerns. Otherwise a judge may be of the view that you have just manufactured such concerns only when being pressed in court for payment. The concerns have more credibility if you bring them up earlier.

If you have the instructions to the paralegals in writing, or your earlier concerns to him in writing, that will be very helpful. If you do not, you can still testify about the instructions or conversations. You may want to make notes now about those so that you remember dates and details, as a trial could be many months away.

If you wait until you are sued, it will probably be very difficult to then try to go through the assessment procedure. A court can extend the time limit to apply for an assessment but needs to have a valid reason why you delayed. Waiting until you were pressed for payment is not likely to be seen as valid. There may be no need to go through an assessment though, if a judge reduces the amount owing to just that where it is clear what work is done or the lawyer had your instructions to do the work. But you will not be able to use the assessment as a form of appeal if the judge does not agree with you and orders payments even for those items you did not understand or say were not authorized.

I cannot give you an opinion or advice as exactly what to do or the odds for success. The site prevents us from giving legal advice or opinion. Plus I would at the least need to review the full bill and discuss this with you to give any meaningful assessment and that is not possible through this site. I hope the above is of some value to you (as you indicated also you only wanted low amount of detail), but if you were only wanting to pay if you can get such an opinion, you can get a refund through customer service.

If this was of value to you, you can rate any of the top three categories and I will get credit for my time. If you do not think it was of value, you need not give any rating at all, and can ask customer service for a refund. Rating in the bottom two categories is not necessary to get a refund, it just means my statistics to the site will show a negative reply.