I would like to know how you cost your consultancy work. Do you have charge sheet template? Where you provide number of days required to complete the whole certification work. From gap analysis, documentation, implementation of stage 1 and Stage 2 and certification.
Where you specify work to be done on-site and mandays offsite.
Let me know if you have such template of your charge sheet and plan of action towards completion of ISO 9001:2015 Certification process.
Rates of your consultancy work will depend on various factors, mainly where you are delivering your services (country, state, region...) and your experience working as a consultant. Usually you will need to estimate the hours that you will spend for every phase in the implementation depending on the size of the company, locations, complexity of the products/services, etc. For instance, phases could be divided as follows:
1. Initiation, planning and assessment
2. Implementation of the QMS
Of course you will also need to include in your proposal ho w many hours you will need to work on-site and offsite, considering that remotely hours often cost less than the on-site ones.