Calculate rate and change rate based on total value reaches a target

I AM TRYING TO CALCULATE A MILEAGE RATE SET AT €1.12

WHEN THE TOTAL MILEAGE ACCRUED REACHES 5000 KM, THE RATE CHANGES TO 98c

I CAN MAKE CALCULATE EITHER USING AN IF AND MAX FUNCTION COMBO

BUT I AM HAVING TROUBLE WITH THE ENTRY THAT PUSHES THE TOTAL OVER 5000

HELP PLEASE

BAJ

Change the value in P2 to .98 from 98, and in D3 use

=IF(C3="","",IF(SUM($C$2:C2)>5000,$P$2,$O$2)*C3-IF(SUM($C$2:C2)<5000,MAX(0,SUM($C$2:C3)-5000)*($O$2-$P$2)))

and copy down.