Has your sell-through been steady out of season? If you sell-through in recent months has been low that will lower your max units stored at Amazon. I suggest finding a 3rd party to store your goods in the USA. Then as you have availability at Amazon, ship inventory in. The dates are great suggestions. However, their warehouses don’t stop receiving inventory that day. They are just letting you know they are only confident inventory that gets to them by those dates will be available for holiday sales.
Increasing your inventory storage limits:
If you stay in stock in October, you will see your inventory go up in November, and then December, etc. However, once your sell-through slows down again, you will see your max units in storage decrease.
I know - it stinks that you have to add another point on your supply chain. However, Amazon isn’t going to change its policies.
This is what we did. It works. Our storage limits have remained high / increased in recent months. Currently, they’re at 6000 units. It was 3,000 units in June.