NFHS End-of-Period mechanic

[ilyazhito]

It makes sense. I don't get why I am expected to blow the whistle at the end of the period with no try when I am working non-IAABO games. Is that because the whisthe is required at the end of the period in the NFHS manual, or is it just cultural expectations? I don't blow the whistle if there is no try, unless the gym I am in has no horn (usually the case for rec games). I only blow the whistle at the end of timeouts, to begin periods, or if the throw-in comes after an extended delay.