Most US universities will say “we expect you to maintain the present level of academic performance” in your acceptance letters. It’s rare to hear that a US university rescinds your offer due to one or two marks off your final grades in comparison to your predicted. However, they are within their rights to rescind your offer if you significantly drop from the grade you were predicted.
In contrast, predicted grades matter more for UK universities. When you’re applying, your predicted grades need to reach the IB requirement grade for your intended major to be considered. When you get your contextual offer, it will likely be somewhat near your predicted grades. You’ll need to achieve that score in the final exams in order to enroll. For example, an offer for studying History at UCL is 38 points with total 18 points at HL. If you don’t get that, you may have to go to your Insurance choice. Your Firm choice may be flexible if you’re a grade or two off their requirements, but it’s not 100% guaranteed.
Your Insurance choice is your second choice university that you put on UCAS. It has a lower conditional offer than your Firm. If you had Loughborough as your second choice with an offer of 35 points but end up with 36 points, you could go there instead of UCL.