What is wrong with the function G8?

G8 v Xfx --CUMPRINC(D$5,D$3*D$2,B$4,48,48,0) B C D E H 1 Input Area Payment Dates & Cumulative Interest 2 Equipment Cost $25,000.00 # of Months/Year 1# 12 First Payment Date 9/1/2021 3 Down Payment $ 5,000.00 # of Years in Loan 5 Last Payment Date 10/1/2026 4 Amount of the Loan $ 20,000.00 Loan APR 6.0% Year of Last Payment 5.08 5 Monthly Payment $ 386.66 Monthly Rate 0.5% 6 Beginning Monthly Principal Ending Cumulative Cumulative 7 Pmt # Balance Payment Interest Paid Reduction Balance Principal Yearly Interest 8 1 $ 20,000.00 $ 386.66 $ 1,200.00 $ 286.66 $ 19,713.34 B$4, A8, A8,0) 9 2 $19,713.34 $ 386.66 $ 1,197.75 $ 286.66 $ 19,426.69 $ 288.09 10 3 3 $19,426.69 $ 386.66 $ 1,195.36 $ 286.66 $ 19,140.03 $ 289.53 11 4 $ 19,140.03 $ $ 386.66 $ 1,192.83 $ 286.66 $ 18,853.38 $ 290.98 12 5 $ 18,853.38 $ 386.66 $ 1,190.15 $ 286.66 $ 18,566.72 $ 292.43 13 6 $18,566.72 $ 386.66 $ 1,187.31 $ 286.66 $ 18,280.06 $ 293.89 14 7 $ 18,280.06 $ 386.66 $ 1,184.30 $ 286.66 $ 17,993.41 $ 295.36 15 8 $17,993.41 $ 386.66 $ 1,181.11 $ 286.66 $ 17,706.75 $ 296.84 16 9 ? ? 17 10 $ 17,4 18 11 $ 17,1 CUMPRINC 19 12 $ 16,8 Rate DS5 = 0.005 $ (1,103.81) 20 13 $ 16,5 Nper D$3*D52 = 60 21 14 $ 16,2 Pv B$4 1 = 20000 22 15 $ 15,9 Start_period AS 1 23 16 $ 15,7 $ End period A8 1 = 1 24 17 $ 15,4 25 18 $ 15,1 = -286.6560306 26 19 $14,8 Returns the cumulative principal paid on a loan between two periods. a 27 20 $ 14,5 Rate is the interest rate. 28 21 $ 14,2 29 22 $ 13,9 30 23 $ 13,6 Formula result = $ S 286.66 31 24 $ 13,4 $ 885.71 Help on this function OK Cancel 32 25 $ 13,1 33 26 $12,833.60 $ 386.66 $ 1,076.51 $ 286.66 $ 12,546.94 $ 324.72 34 27 $12,546.94 $ 386.66 $ 1,066.85 $ 286.66 $ 12,260.29 $ 326.35 35 28 $ 12,260.29 $ 386.66 $ 1,056.61 $ 286.66 $ 11,973.63 $ 327.98 $17,7 Function Arguments 1 A = 1 1 26 20 11 072 62 296 66 105 75 206 66 11 686 220 62