We do that all the time. Describuing the scope of services under Basic Services does not need to mean that they are provided for a fixed fee. They can be provided under another arrangement, using the same contract.
All you need to do is modify the clause regarding the fixed fee to apply to the phases intended, and then add the phrase "construction Administration" or whatever else is being provided on an hourly basis to the clause which describes charges for "Additional services"
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Jerry Roller AIA
Firm Owner/Architect
JKR Partners
Philadelphia PA
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