This is completely speculative and likely very wrong, but:
Computer order for school districts were backed up because no one anticipated the loss due to COVID and the budget is only so big to order so many. This means we didn’t get all the replacements we needed and then suffered more losses during the school year, plus with the implementation of online school as an option. As we can’t afford name brand, like Windows (my school bought chromebooks), I assume that April and May is when the school districts put in orders for next year’s laptops.