I need that last question answered what are the weaknesses are inherent in this estimating approach

Paste B I U V . VVA v A4 X V fx A B C 191 17/ 4 AFT LILD RULLI IFIANAULIFILITI 2IS AJJIJITITILITT. N CH. 5 EXERCISE 5 Exercise Figure 5.1 is a project WBS with cost apportioned by percentages. If the total project cost is estimat estimated costs for the following deliverables? Router systems project Cost: $800,000 + Implementation 10 00 Definition Design 10% 10% 50% 10 11 12 In-house Customer testing 13 Objectives Requirements testing & review 4% 6% 14 40% 10% 15 16 Inputs Outputs Files Interfaces Programming 3% 3% 3% 9% 22% $320,000 20 Design $176,000 21 Programming $320,000 22 In-house testing What weaknesses are inherent in this estimating approach? (Enter response) 25 26 27 28 29 30