Help translating If/Then fn to LOOKUP

Try

=R3*LOOKUP(P3,{0,30,35,40,45,50,55,60,65},{0.07,0.09,0.11,0.15,0.24,0.36,0.62,0.87,1.51})

if you create a table

A B
0 0.07
30 0.09
35 0.11
40 0.15
45 0.24
50 0.36
55 0.62
60 0.87
65 1.51

I think that table would work

then use

=vlookup( P3, table range, 2, true) * R3

worth testing I have the tiers correct

vlookup when the last element is TRUE will find the lowest matching value in the table

so if P3 between >=55 and <60 say 58
then it would look through the table and see that the nearest lower value to 58 is 55 and so use 0.62

now you can add as many tiers as you like

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