What is required is implementation of 60.4 where a person whose rate is not in the BOQ replaces a person whose rate is in the BOQ. Is the difference between the two rates a compensation event which requires to be assessed as Defined Cost + Fee or do you simply pay as long as the difference is less or equal to 0.5% of the total contract value.
I may be getting hold of the wrong end of the stick … or it may be the other way around !
Option B is an OUTPUT based contract and the Employer is therefore paying per unit of output. 60.4 covers changes in these quantities where the change is sufficient for the change in costs not to match the pricing model. Therefore the Contractor is paid the change in Defined Cost + Fee as opposed to just change in quantity times original rate.
What you seem to be implying in your question is a change in your INPUT costs. This is not a compensation event and therefore 60.4 does not apply.
If I have not understood the question properly, please do clarify.