How accurate has Waze Travel time been for you?

I only use it for how long it will take my wife to drive from home to work - a route she takes everyday and we know roughly how long it takes just on experience alone. I thought the integration would come in handy as delays due to traffic and/or accidents tend to occur mostly around this time of year. From the very start, Waze added 20 minutes on top of her usual journey, so we assumed that there must’ve been an accident or traffic jam that day, but it seems to just regularly add 20 minutes to her regular travel time somehow.

I’ve been playing around with the icloud3 integration which uses waze as well, but they have a waze_realtime option that shows a far more accurate representation of the time it takes to get to and from the location. The waze phone app also aligns more with the icloud3 representation which suggests that the waze travel time integration is either using a different route or non-realtime data (or both).

I do live in an area where there isn’t an abundance of waze users, so I am wondering if that plays a bit of a role as well, so I’m curious to know how accurate this integration has been for the rest of the community and if there was an option to switch to real-time data as well because I cannot seem to find that in the documentation so far.