In short, yes.
In full:
The easiest way to think of the billing system is a series of yes/no questions. Every time you make or receive a call, the questions go in this order:
1) Is the other person you're talking to in your 5?
2) Is it between the hours of 9pm and 7am? (or earlier if you buy early evenings)
3) If none of the above apply, these are daytime minutes.
Once the systems answers yes, it's done. That's the category it puts your call under. In you case, it shouldn't matter because both the 5 and the E/W are Unltd.. But on the $25 My5 with 1000 E/W instead of Unltd. it surely will.
Obviously if you add in roaming, long distance, etc. the series of questions gets more complicated. But that should cover the basics for what you asked and what most people need to know for daily use.
Hope that helps you!