Confused about fico scores...

I recently checked my fico score using one of those free credit score websites, and to my surprise, it wasn't the same as the one I got from my credit card company a few weeks ago. What gives?

I'm thinking of buying a house soon, so, naturally, I've been keeping a close eye on my credit score. Now, the confusing part is that the scores from these different sources don't match up.

Based on this article, the different versions meet different needs in the credit scene https://consumerattorneys.com/article/why-are-fico-score-versions-different

But how am I supposed to know which one the mortgage lenders are going to look at?