Should a patient on medium-dose ICS/LABA with normal PFTs, but who shows a greater than 10% decrease in FEV1 if their PFTs are done after 24 hours off their inhaler, be started on a biologic?

A little more clinical information would be useful to better answer the question. How well controlled is the patient on the LABA/ICS? What is the ACT score? The FEV1 decreased by greater than 10% (with volume >200 ml?) when LABA/ICS was stopped for 24 hours - how quickly did it normalize when the in...

Thank you to Dr. @Dr. First Last for his answer. To add some information, the patient is asymptomatic and not needed a steroid burst for respiratory infections. Their FEV1/FVC also drops if spirometry is done when they are off their inhaler for 24 hours. Also, if they miss a dose or two of their inh...