ADBLUE/DEF replacement

[PoloDieselMan1960]

Hi Gents,

1st time caller, long time listener.....lol

I have a 2015 X5d.
I had my DEF refilled when I had an oil change at my BMW service place (not dealer).

They charged me $165 for 2 gallons. Seemed a little HIGH since online says I could buy for ~$30/gal. They indicated that they had to "re-calibrate the computer when adding".

Question: Is it as simple as just "adding the DEF"? It seems simple.

I know that there's a computer that says "X # of miles left" if it runs way low, but does the computer "have" to be reset every time adding DEF?

Thoughts??