Anyone have experience with acquisitions of residential cleaning companies?

I currently have an LOI out for a small but profitable residential, Airbnb, and small office cleaning company in Southern California. I’m looking to learn from experienced operators in this space what key questions I should be asking when meeting with the seller. The business is already SBA pre‑qualified and has been operating successfully for over 20 years, so my focus is less on the revenue and more on understanding the business itself. Separately, I’d like to gain perspective on the typical pricing structures for these types of services. The company currently operates on an hourly basis, but I want to understand whether the industry standard leans toward flat rate or hourly, along with the pros and cons of each. I’m also interested in how to effectively transition from one structure (hourly) to another (flat rate), and what best practices exist for implementing such a change. Finally, I’m seeking general advice about the industry overall and what you see as the current and future challenges to navigate. Thanks, Vishak