Automate list size reduction

I'm going to try to lay this out succinctly, let's see how I do:

I am trying to build a flexible re-usable sheet to dump two reports into and receive a comparison report.

One report has a list of date time stamps for a variable number of work orders (Dt), each with a variable number of entries. The second has a list of date time stamps for a variable number of inspections that also have work orders (Mt), but also have way more work orders, and often are missing inspections for some work orders entirely.

What I want out the end is a report for each produced time stamp (Dt) that tells me how separate it is from the most recent (before or after) inspection (Mt). What I do right now is basically a min(abs(Dt-filter( (Mt)*(does Mt work order match Dt work order)))).

It works, but oh em gee the computation, because every Dt entry gets compared to EVERY Mt computation.

After that I just look at a pivot table of the results to see max time and average. This tells me if people went too long saving parts (Dt time stamp) but NOT measuring parts (Mt).

Is there a way to take each of the original lists, have them pushed/pulled to a variable width series of columns (one per Work Order), then have a variable length comparator look at the first set of columns and do that "time to closest inspection" but only with the matching column from the second set of data?

I know I could do it if I make them part of a data model and just slowly go through each work order, but I'd prefer it to just spit out the results at the end so I can hand this sheet off to others and not have to manually do the adjustments every day.

Let me know if this isn't clear and I can try to set up some example mini-tables or something to better explain my gibber jabber above.

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