Centering data in one column between two adjacent rows

[gallagt01]

Hello,

I'm wondering if it's possible to center data in one column between two adjacent rows without simply merging/centering two cells in one column.

Here is a picture of what exactly I'm looking to do.

20170413_095615.jpg

My company wants to document machine hours every time we change that machine's "tooling."

I wrote into the cells in the "elapsed" column the correct formula to automatically generate how many hours elapsed between each "tooling change" (so when I enter a new "date of tooling change" and the machine hours at the time of the change, the amount of time that elapsed after the previous tooling change is displayed).

But I want that information be centered between the hours of the tooling change, much like how I have it in the first two rows in the above picture (which I did by merging and centering the cells in the elapsed column). I want the "19" in my elapsed column to center between the 81 and the 100, etc etc. It doesn't seem possible to center the subsequent elapsed data unless I duplicate rows and merge/center accordingly (as seen in the bottom chart in the above picture), though.

Any help on this would be much appreciated. Thank you!