This user is trying to solve a problem that spreadsheet formulas were never designed for elegantly. The SEQUENCE approach they found works for all 24 hours of a year, but they need only a 12-hour window per day. That formula is a clever hack, but it is also a brittle one. Relying on a single formula to pack 13 hour-slots (9:00 to 21:00 inclusive) into a sequence that spans multiple dates means you are one miscalculated argument away from broken timestamps or a sheet that refuses to calculate. The community's instinct to ask "is there a better way?" is the right one.
The practical answer here is not a better formula, it is a fundamentally different tool. An AI-native spreadsheet can interpret plain language like "generate hourly timestamps from X to Y, only between 9 AM and 9 PM" and produce the exact list without you debugging SEQUENCE multipliers or fractional day increments. The user's current workflow forces them to translate a human need ("hours during business time") into arcane arithmetic: multiplying the day difference by 3 and 24, then dividing by 24. That is not productivity; that is translation overhead. A tool that understands context saves you from that middle step.
What this means for you is straightforward: if you frequently build date-hour sequences, schedule batches, or model time windows, stop treating spreadsheets as pure calculation engines. The user's formula is correct for a narrow case, but it fails the moment you want to exclude weekends, skip holidays, or shift the window to different hours. Each change requires a rewrite. An AI-native approach lets you describe the rule once and regenerate the sequence in seconds. You keep the flexibility of a spreadsheet without the cognitive tax of remembering which function arguments control time intervals.
The takeaway is not that SEQUENCE is bad, it is that the user's instinct to question the formula reveals a deeper truth. Legacy spreadsheet logic forces you to think like a machine. Modern tools should let you think like a person. Stop asking how to bend a 24-hour formula into a 12-hour one. Instead, ask your tool to understand what "only business hours" means. That shift transforms how you build your data.