Many customers require that vendors follow their scripts step-by-step, even if the logic and flow aren’t particularly logical for the vendor’s software. This often results in long, frustrating demo sessions for vendors (and customers as well).
In addition to the other tactics suggested previously, here’s another method to consider: Follow the customer’s script and demonstrate each proof point in accord with the script, initially – however, if/when your customer begins to get comfortable with you and your offering (and if you have earned sufficient credibility), you can consider asking to change some sections to enable to better flow (for the customer’s sake, of course) and better visualization of the capabilities they’ve requested (for the customer’s benefit, of course).
In the worst case, your customer simply says, “No”. In the best situation, they say, “Sure” – and you are able to re-order and rearrange your demo in accord with your interests. If you do make changes, be sure in each summary section to identify which capabilities were covered in that section (“We just showed you items 401, 402, 403, 404, and 452 – are you comfortable that we handled these sufficiently?”).