My guess is that when it was constructed 50 years ago, the "device" was engineered with the units that were familiar or already organized into formulas to plug

My guess is that when it was constructed 50 years ago, the "device" was engineered with the units that were familiar or already organized into formulas to plug data into. In the early to mid 60's, simple extremely limited dedicated calculators were a new thing and hard to get. Not at all like the tech in our world we take for granted, numerical analysis was much harder to accomplish. Of course today we have vast computation resources right under our fingertips. How hard is it to translate from one set of units to another? No doubt on issuing a report of their test results, the output will be expressed in whatever units anybody wants, no trouble at all...