This is just in the interest of full disclosure, the calendar that you referenced is not EasyPHPCalendar. It is a service offered by nadn.org. Although the calendar uses the same month header image as EPC, it is not EPC.
At best, it was Brian moonlighting several years ago... at worst, it's based on intellectual property from an early version of EPC.
I've worked with EPC since I think version 3 (about 10 years), and cannot attribute the output to any version that I know of.
That being said, it doesn't change the validity of what Brian said above.
You can also find a couple of old posts where I reference a date-picker/availability/booking mod [here
, and here
] which is a possibility for you if you're booking full days. Adding the AM/PM option hasn't been attempted, but would add a lot of complexity (I think).
EPC Tutorials... We're here to help!
Offering custom integration services. Contact me here
* Not affiliated with EasyPHPCalendar or NashTech Inc.