Can working capital targets be set differently for a business with a strongly seasonal cash cycle?

Yes, and for a genuinely seasonal business it often should be, since a working capital target is meant to reflect the level of working capital the business normally needs to operate, and a single generic figure, or a plain trailing-average approach, can misstate what is actually normal depending on where in the seasonal cycle the closing date happens to fall.

A business that builds up inventory or receivables ahead of its busy season, for example, will look very different on the closing date than the same business measured at the low point of its cycle, even though both are entirely normal for that business. Parties dealing with a seasonal business commonly negotiate a target that accounts specifically for the closing date's position in that cycle, sometimes using historical figures from the same point in prior years rather than a flat annual average, precisely to avoid an adjustment mechanism that penalizes one side simply because of when the deal happened to close. This is a detail worth raising early in negotiations for any business with meaningful seasonality, rather than defaulting to a generic target designed for a steady, non-seasonal business.