App disparities

[Gazabone]

I've always thought of astronomy being  an exacting science as far as measurements are concerned.  For example, John Couch Adams finding Neptune using maths (a heck of an achievement!) but I'm curious about the disparity of various apps to help find one's way around the night sky.

As an example, looking at the celestial coordinates given for M101 (the Pinwheel Galaxy) for the following apps are;

Stellarium - RA 14h 03m 44s    Dec +54º 16' 38"

Star Chart - RA 14h 03m 37s   Dec +54º 17' 57"

Star Walk - RA 14h 03m 18s   Dec +54º 20' 59"

Star Walk 2 - RA 14h 03m 18s   Dec +54º 20' 59.99"

Go Sky Watch - RA 14h 03m 13s   Dec +54º 20s 57"

The RA measurements are not very different but the Dec measurements show rather more disparity.  I think each of these apps are great in their various ways, some are free, some aren't but I am a little surprised that there isn't uniformity.  I do wonder if John Couch Adams had more accurate measurements, and if so, in this day and age, why haven't we?