If you switch stains you are committing yourself to having to strip the house to remove the other stain before installing a new product. If you don't, you are looking at an even more costly fix when it fails due to product incompatibility. If the product (Wolman) as been maintained on a regular basis according to the manufacturer specs, then you should be fine to clean as directed and reapply. If the maintenance is not on schedule or if you are uncertain of the home's maintenance history, you could end up with an uneven looking result is some areas are faded or worn and others are not.
If you could post some photos of the home in it's current condition that would help.