In order to make sure the bridge is in the right location, check the feet in relation to the f-holes. If you know your basses string length, use a good solid ruler and measure from the end of the nut to the top of the bridge. Over time, the technique of slapping will cause the bridge to move as we are constantly pulling the string out and relieving the tension on the bridge. This is especially true for those of us using low tension strings (gut’s velvet’s, tuned down solo strings, etc.) A simple knock back into place is usually all that’s required.