Brewing software estimates the attenuation of yeasts. It's not a consistent figure from brew to brew unless everything is exactly the same, and that pretty much impossible. Even with the same yeast. If you record your figures your predictions will improve.
SG constant, so dry hopped today.
I will bottle next Tuesday evening.
I drank my hydrometer samples and enjoyed them, so in about four weeks I will be able to enjoy the fruits of my labours(and worries)!