Well the formula from Google sheets is this:

=if(and(((A3*B3)**C3)/144>0,((A3*B3)*C3)/144<0.1),mround(A3*B30.32,0.25),

if(and(((A3*B3)**C3)/144>0.100001,((A3*B3)*C3)/144<0.15),mround(A3*B30.3,0.25),

if(and(((A3*B3)**C3)/144>0.150001,((A3*B3)*C3)/144<0.2),mround(A3*B30.28,0.25),

if(and(((A3*B3)**C3)/144>0.20001,((A3*B3)*C3)/144<0.25),mround(A3*B30.26,0.25),

if(and(((A3*B3)**C3)/144>0.250001,((A3*B3)*C3)/144<0.3),mround(A3*B30.24,0.25),

if(and(((A3*B3)**C3)/144>0.30001,((A3*B3)*C3)/144<0.35),mround(A3*B30.22,0.25),

if(and(((A3*B3)**C3)/144>0.350001,((A3*B3)*C3)/144<0.4),mround(A3*B30.2,0.25),

if(and(((A3*B3)**C3)/144>0.40001,((A3*B3)*C3)/144<0.45),mround(A3*B30.18,0.25),

if(and(((A3*B3)**C3)/144>0.450001,((A3*B3)*C3)/144<0.55),mround(A3*B30.18,0.25),

if(and(((A3*B3)**C3)/144>0.550001,((A3*B3)*C3)/144<1000.55),mround(A3*B30.15,0.25),0))))))))))

Edit: Looks like the forum takes out the multiply symbols… See below for image of code.

Edit 2: Found this burried in Appsheet. Looks like Appsheet does a conversion and applies it at some point.

if(and(((RC[-3]*RC[-2])*RC[-1])/144>0,((RC[-3]*RC[-2])*RC[-1])/144<0.1),mround(RC[-3]*RC[-2]*0.32,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.100001,((RC[-3]*RC[-2])*RC[-1])/144<0.15),mround(RC[-3]*RC[-2]*0.3,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.150001,((RC[-3]*RC[-2])*RC[-1])/144<0.2),mround(RC[-3]*RC[-2]*0.28,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.20001,((RC[-3]*RC[-2])*RC[-1])/144<0.25),mround(RC[-3]*RC[-2]*0.26,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.250001,((RC[-3]*RC[-2])*RC[-1])/144<0.3),mround(RC[-3]*RC[-2]*0.24,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.30001,((RC[-3]*RC[-2])*RC[-1])/144<0.35),mround(RC[-3]*RC[-2]*0.22,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.350001,((RC[-3]*RC[-2])*RC[-1])/144<0.4),mround(RC[-3]*RC[-2]*0.2,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.40001,((RC[-3]*RC[-2])*RC[-1])/144<0.45),mround(RC[-3]*RC[-2]*0.18,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.450001,((RC[-3]*RC[-2])*RC[-1])/144<0.55),mround(RC[-3]*RC[-2]*0.18,0.25),if(and(((RC[-3]*RC[-2])*RC[-1])/144>0.550001,((RC[-3]*RC[-2])*RC[-1])/144<1000.55),mround(RC[-3]*RC[-2]*0.15,0.25),0))))))))))