How Dmax analysis results effects the final photograph.

I was a Crossfield 656 Drum Scanner operator and highest black was coming from Leica IIIC with Elmar 50mm and it was 3.5 , film was Kodak EPP. I scanned 8x10 US Ford Slides to anything and this was the highest in 4 years , year 1994-98.

Was it the thing called DMax ?

I visited DR5 and it says Delta have 4.5 , I remember Photo Engineer told about cine film copying film and was Dmax was 4.

Can someone shed a light on Delta 100 films and I am very excited.