Deciseconds?? There's your problem. Always work in seconds when forcing a function for your users.
Deciseconds are just uncommon. But the problem here is that the user didn't expect the "1" to be a unit of time but instead a boolean value. He never wanted a timer in the first place.
By the way, not making the unit of time clear is a pet peeve of mine. The unit is never obvious, seconds and milliseconds are the most common, but you don't know which one unless you read the docs, and it can be something else.
My preferred way is to specify the unit during the definition (ex: "timeout=1s") with a specific type for durations, second is to have it in the name (ex: "timeoutMs=1000"), documentation comes third (that's the case of git). If not documented in any way, you usually have to resort to trial and error or look deep into the code, as these values tend to be passed around quite a bit before reaching a function that finally makes the unit of time explicit.
Do some think that 900ms, or 800, or some other sub-second value is really what we need for this error condition? Instead of, you know, not creating errors?
You might be more familiar with decimeters, deciliters, decibels or the base-10 (decimal) numbering system.