No, just some quick in my head maths.
Here's it worked out accurately, and yes I'm slightly wrong.
If an EV battery charged to 100% looses 2% of it's remaining capacity each month for 6 months, it works out as this.
Month 1 the remaining capacity drops from 100% to 98%.
Month 2 the remaining capacity starts at 98% minus 2% leaves 96.04%.
Month 3, 96.04% - 2% = 94.11%.
Month 4, 94.11% - 2% = 92.22%.
Month 5, 92.22% - 2% = 90.37%.
Month 6, 90.37% - 2% = 88.56% remaining.
This is a loss of 11.44% over 6 months of sitting, so I was 1.44% out, but that's snot even remotely close to being flat.