"Accuracy" is a very scarey and misused term when people talk about navigation features.
Location accuracy applies to the GPS and the signals it provides to a program like Streets&Trips. It has absolutely nothing to do with addresses.
The GPS tells the navigation program where it thinks it is on the surface of the planet and the navigation program displays that location on whatever maps it has loaded. That's it.
Addresses are a whole different subject.
The maps contain multiple databases. These databases include regions, like states and provinces, city names, street and road and highway names/numbers and house numbers.
The last one - house numbers - is problematic for map makers and users, too.
The house numbers are normally not placed on the street individually. In most map products the house numbers are allocated in groups which are in turn associated with a particular block on the street. So, in the map database the 500 block of Davis Street might show that the house numbers from 501 to 558 are in that block somewhere.
The map maker now has to guess at a couple of things about how to show where those house numbers are situated. First, they will probably assume that even numbers are on one side of the street and odd numbers are on the other. That's usually a fairly safe assumption. But not always.
Next, they will probably assume that all of the house numbers in the range are used on longer blocks but on shorter blocks perhaps only every second number is used. This one is pretty iffy because it can vary all over the place.
Finally, in order to figure out where to position each house number on the street they will probably assume that each lot is approximately the same width at the street. Again, usually a safe assumption but not always.
So, if you think about those assumptions and compare it to the reality of your lot on your block on your street, you might find it easy to understand how it is that your house is not in the same place on the planet as Streets&Trips or other map programs think it is.
Keep the distinction between the GPS location and address locations in mind, always.
When you get your GPS and connect it to Streets&Trips, when you go out in the yard and fire things up you will see your location plotted fairly accurately on the map display.
But when you search for your house address it's still not going to change where Streets&Trips thinks it is. That has nothing to do with the GPS location plotting.