AppleScript conditional statement rules

I need a script to run between 9pm and 6am and I'm struggling to understand why this isn't working. I've tried with and without parentheses.

From the suggestions here, I removed "as string" but then got an error when I tried to run the app.

I figured out the error came from another line in the code that I didn't include in the example.

set myTimeB to (round ((time of date ((current date) as string)) / 60) rounding down) mod 5 = 0 --every 5 minutes

Any idea why this needs "as string" to function?

set myTime to time of (current date) --as string

if (myTime > 21600) and (myTime < 75600) then
    display notification "it's between 6am and 9pm"
else
    display notification "it's between 9pm and 6am"
end if

Update to address totally changed scope of original question:

The issue as I see is that of date and as string in ((time of date ((current date) as string)) / 60) do not belong there. It should just be:

set myTimeB to (round ((time of (current date)) / 60) rounding down) mod 5 = 0 --every 5 minutes`

• (time of (current date) returns an integer, so it's all set to be divided by 60. There is no need to be coercing it to a string.
• of date makes no sense in the equation.

Original answer:

The following works for me:

set myTime to time of (current date)

if (myTime > 21600) and (myTime < 75600) then
    display notification "it's between 6am and 9pm"
else
    display notification "it's between 9pm and 6am"
end if

Note that originally, myTime was a string and you were comparing it against an integer. Now it's being compared against the same class.

If you run the following in Script Editor:

return class of time of (current date) & class of 21600

It returns: {integer, integer}

While the result of:

set myTime to time of (current date) as string
return (class of myTime) & class of 21600

It returns: {text, integer}