I use this same method to sleep my batch files, but there is no reason to call a separate file, use this in your file, example script below.
Code
@echo off
:: Put your commands here...
Echo this is calling sleep, with a parameter
Echo The syntax is Call :Sleep Parameter [ you have to call the label with the colon before it]
Echo Also, any label you call like this needs to end in Goto :EOF
Echo the paramater is not equal is seconds, only the amount of loops.
Echo You will have to time and find numbers that are equal to your delay.
Echo This is so much better than using Ping.exe
Echo The ping command will be detected by firewalls, like Comodo.
Echo Also, the ping.exe will be in the task manager.
Echo Important, having echo on will make the delay way longer..
Echo.
Echo example script below.
start notepad|Start notepad|Start Notepad
call :Sleep 10000
Echo Back from sleeping....
start notepad|Start notepad|Start Notepad
call :Sleep 10000
Echo Back from sleeping....
start notepad|Start notepad|Start Notepad
echo Random Sleep Delay
Call :Sleep %random:~0,4%
:: True End of File is Here.
Goto :EOF
:Sleep
Set "_Res=0"
:Resume
Set /A "_Res=%_Res%+1"
If %_Res% Leq %1 Goto Resume
Goto :Eof
::--