[SOLVED] Quick question: Time it takes to reach a temperature?

Hello! What a great forum, has helped me many times.

I have two columns of data, D and E with time in the E column and rising temperatures in the D column.
My question is that I would like to the find the time between when column D exceeds 30 and when it reaches a value like 150 by referencing the time column E.

I solved this using the VLOOKUP function: =(VLOOKUP(150,D12:E400,2,TRUE))-(VLOOKUP(30,D12:E100,2,TRUE))
However, I had to move my time variables from column C to E in order for VLOOKUP to work. (It won't accept a lookup value of -1 for the column designation)

Is there another way to do this?

Thank you in advance!