What could/would cause a newly placed 3x1 lot price to change?

I've been running my S2 Ultimate on my laptop for over a year now and this morning when I placed 3x1 lots in the neighborhood I've been building the 3x1 lot prices have changed from 900 to 1000 for no apparent reason. This is not a custom neighborhood. I used the Crystal Springs template for this neighborhood. I have never attempted to change an empty lot price and to the best of my knowledge I have no mods or hacks that would affect the lot price. In all the years (about 15 years) I have played The Sims I have never seen this happen until today. Not in TS, TS2, TS3 or TS4 (yes, I have all 4 series ).

Laptop specs:
Windows 8.1 64bit
AMD FX-7500 Radeon R7 10core (4C+6G) 2.10 GHz
6 GB RAM (4.97 usable)
Full Windows touch support with 10 touch points

What I would like to do, if possible, is set the 3x1 lot price back to its original price of 900. If it's not possible then I'd love to have an explanation as to why the price changed all by itself. Did EA/Maxis add code to the Ultimate Collection that would cause lot prices to go up based on the value or number of lots placed in a neighborhood? Why would it not show up in more than a year of playing S2 Ultimate on my laptop until this morning?

While it should not have any bearing on this issue I do have about 28k (and climbing!) in CC in my game. Some of the CC are 3t2 and 4t2 conversions.

ETA: I have placed more than one 3x1 lot to see if it was just a glitch with the first one I placed, however all of the ones I placed showed as being 1000 in price instead of 900.