How is the next autoattack availability calculated after a debuff falls off between attacks?

As the title states I'm wondering if anyone knows what the next timing is of an auto attack is if an attack speed slow were to fall off between auto attacks.

It's my understanding that the time for between auto attacks is easily calculated with the following formula (2.5 APS cap not shown): secondsToNextAttack = 1 / (baseAttackSpeed * (1 + bonusAttackSpeed)) * (1 - attackSpeedDebuff)

This will give the delay until the next auto attack in seconds given the attackSpeedDebuff stays applied for the duration of the delay. What I'm wondering is if a debuff falls off between attacks when would the next auto attack be ready to go? Let's say the attack speed slow falls off after waiting 60% of the auto attack delay, is the attack available at the time set by the original auto attack or is it recalculated with the new delay after the debuff falls off for the percent of time still necessary to wait?

Sample formula below (please note, while the attackSpeedDebuff is still in the formula consider it 0): secondsToNextAttack = (1 / (baseAttackSpeed * (1 + bonusAttackSpeed)) * (1 - attackSpeedDebuff) * percentDelayRemaining

Any help would be appreciated, thanks.