help to define this logic in Mathcad R15, while using data from excel

Hi,

I am using a data set in MS excel. From the given inputs -known (Nominal Ratio -NR & Power-P) I need to select the output (unit Size). The logic used is as follows:

For the given value of NR select the lower value, from table. For eg if given NR is 6.1, then select 5.6
For the given value of P select the higher value, from table. For eg if given P is 83.0, then select 124.0
Hence result is 160 Unit Size.

Please also refer attached image.

Can anyone help to define this logic in Mathcad R15? and also make use of the data from Excel

Thanks

Deepak