Instead of a paragraph rule, which I assume you are displaying in a section rule, can you use a paragraph rule for the part that doesn't change, and display a property rule for the part that does change, since by design, property rules assume their value will change. Your code would transfer the appropriate value from your data page to the property on the primary page before you display your section which exposes the property to the screen. FOR EXAMPLE:
Paragraph rule says: "The temperature in Boston today reached "
Property is called .highTemperature.
Your section would display the paragraph and then the property so that if .highTemperature is set to 70, the user would see