Keeping kiln dried lumber DRY.

Here’s my question: I live in north east OHIO. The 15×30 outdoor shed also serves as a my dehumidification kiln. Kiln itself is 15×6, insulated, heated and sectioned off from the main storage area. It is a gambrel type shed/barn. I can dry smaller loads of harwood in my kiln. After the batch is dry enough for use, the next load has to go in. How long can I store the DRY load above in the sheds attic?(Gambrel roof design allows me to stand up in the middle, I can store alot of wood up there) The dried wood is in the 6-9%MC range. Is it possible for the dry load to re-absorb moisture?
Think about this; You can buy dried hardwood from Lowes, HomeD, lumber yards etc… They have the lumber sitting in isles, on store shelves etc. Have you ever though about how long those particular boards have been sitting on the store shelves?
When you walk into those huge stores, the relative humidity is pretty much equal to the outdoor enviroment. “equalibrium”
So DOES wood re-absord?
Thinking further- Store bought lumber has to make the journey from kiln to wholesaler, to retailer. Sometimes traveling by train, truck etc. And again spends some time sitting on shelves before being bought.

So will the wood go from say 7% to 10-15% in a matter of days, weeks, months, or never?
Many times when i buy wood for a project, it sits for a few weeks before use. And I know my “garage shop” is not less than 30%humidity.

Very confusing when you think about the science behind it. Please help. Thank you JAMES- Ohio

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