The practical difference is that service is reactive and experience is designed. Service quality is judged at the moment something has gone wrong, which is important and infrequent. Experience is judged continuously and mostly unconsciously: how quickly you replied, whether the quote was clear, whether anybody told them what was happening, whether the invoice matched what was agreed. Those form the impression, and most of them never generate a conversation.
The consequence for a small business is where to look for improvement. Excellent service cannot compensate for an experience that requires the customer to chase, wait without explanation, or ask what happens next. Conversely, a well designed experience produces fewer service situations, because most complaints originate in ambiguity rather than in failure. Reducing the need for service is more valuable than getting better at it.
Look specifically at the silences, which is where small business experience most often fails. The gap between somebody enquiring and being contacted. The gap between agreement and the work starting. The gap after completion where you never speak again. Each of those is a period where the customer is forming an impression with no input from you, and filling them costs a message.
The other place to look is the transitions, because a customer feels the seams of your process even when each part works. Being handed between people, being asked for information you already have, or receiving different answers from different sources all read as disorganisation regardless of the eventual outcome.
The measure worth using is whether somebody had to chase you for anything. That single question, asked of recent customers, identifies more experience problems than any survey, because chasing is what a customer does when the process did not tell them what they needed to know at the moment they needed it.
Map who is responsible for each stage, even in a business of one, because experience problems concentrate at the points where nobody owns the interaction. The gap after a proposal is sent is the classic example: the customer is deciding, nobody is scheduled to do anything, and the silence extends by default rather than by intention. Naming an owner and a next action for each stage removes most of it.