Unity Invoke method delay factor vary device to device

Hello guys, I am using Invoke function to add some delay on my function calls. Code is like this

 void Start()
 {
   Invoke("FirstMethod",10);
   Invoke("SecondMethod",20)
   Invoke("ThirdMethod",30)
   Invoke("ForthMethod",40)
 }

I have some instructions to display on GUI in my "FirstMethod" that take up to 8 seconds to appear completely , after completion of it i want to display some other instructions that i have written in "SecondMethod" and so on...

I read about documentation of Invoke methods and it seems that this approach will work for my scenario. I want to make sure that how it run on different devices. specially the second parameter that we pass as time in Invoke method is dependent on frame rate or some other factor that may vary on different devices and the order of execution of method may disturb.

Please advise