According to the PMBOK® Guide and PMI Procurement Management standards, this arrangement is a classic example of a Cost Reimbursable contract. Specifically, it aligns with the characteristics of a Cost Plus Fixed Fee (CPFF) contract (or a variation where the " fee " is calculated as a percentage of the initial estimated costs).

Cost Plus Fixed Fee (CPFF): In this contract type, the seller (the event management company) is reimbursed for all allowable actual costs incurred for doing the project work. In addition to the actuals, the seller receives a fixed fee payment.

The 8% Factor: While the question mentions a percentage, in PMI terminology, once a fee is calculated based on the estimated costs and agreed upon, it remains " fixed " relative to the scope of work. It does not change based on the seller ' s actual performance or efficiency, which protects the buyer from the seller unnecessarily inflating costs just to increase the fee (a practice prohibited in many professional standards under " Cost Plus Percentage of Cost " or CPPC, though CPFF remains the standard acceptable structure).

Analysis of other options:

A. Time and Material (TandM): These are hybrid contracts used when the scope cannot be quickly prescribed. They charge per hour or per item (e.g., $\$100$/hour) rather than charging " actuals plus a fee percentage. "

B. Fixed Price Incentive Fee (FPIF): This is a fixed-price contract where the price is set, but the seller can earn an additional reward for hitting specific performance targets (like finishing early). Here, the base is " actuals, " not a fixed price.

D. Cost Plus Award Fee (CPAF): In this type, the majority of the fee is earned based on the satisfaction of certain subjective performance criteria judged by the buyer. An 8% flat charge is a predetermined fee, not a subjective award.

Per PMI standards, the Cost Plus Fixed Fee model is appropriate when the buyer wants the seller to perform the work but the seller is unwilling or unable to assume the financial risk of a fixed-price agreement.