I'll go further and suggest you cancel all nights in Bern and add them to Lauterbrunnen. Bern is a nice place to live but doesn't have much tourist appeal to justify an overnight.
agree, Bern is nice city, but not particularly scenic. A place of business & government.
If there's something specific you want to see in Bern, spending a night there would be worthwhile. If not, I agree with the others that you'd probably enjoy an extra night in the Berner Oberland more.
Agreed. Lauterbrunnen is the closest thing to heaven on earth!!
Is there a particular thing you want to see in Bern?
Maybe the bear pit? Maybe the fountains?
If so, go for it, but be prepared to be underwhelmed. I've stayed there several times but over the years have asked myself if there is anything there I'd want to return to and have decided, "No".
For cities in Switzerland I prefer Basel and Zug.
It is important in the Berner Oberland to allow time for weather issues.
You can always see Bern as a day trip from Lauterbrunnen if you get a cloudy/rainy day while you are there.
I understand from your new post that you have decided the plan.