Heck, let's go straigh to the source to clear this up. From the PADI Specialty Course Instructor Manual:
The way I see it, there is no minimum number of dives beyond the Open Water certification. Additionally, it seems that the certification dives may NOT be combined with Open Water certification dives. Finally, if your O/W instructor was a freak and taught the Wheel, then you will need a little training on the use of the table format of the RDP prior to an Enriched Air course.
II. PADI Enriched Air Diver Course Requirements
1. Prerequisite certification: PADI Open Water Diver, or equivalent.
2. Minimum age: 15 years.
3. Confined water training or practical application sessions may be added at the instructor's discretion. As a preassessment, the instructor may hold a confined water session that includes a scuba skills review prior to the course.
4. Because this program applies Recreational Dive Planner use and skills extensively, the instructor should ensure that students are familiar with the RDP table and how to use it because the Enriched Air RDPs are in table format.
5. Student to instructor ratio is eight to one (8:1), to certified assistant four to one (4:1).
6. Enriched air training dive data.
There are two enriched air training dives required for certification. These may not exceed 30 metres/100 feet, or exceed a PO2 of 1.4 ata., whichever is shallower.
Integrating Enriched Air Diver with Other Courses
Instructors who offer Enriched Air Diver courses may integrate the two required training dives with other PADI continuing education courses. This does not apply to PADI Scuba Diver and Open Water Diver. Specifically PADI Enriched Air Diver students who are also enrolled in another PADI course may complete their Enriched Air Dive at the same time they complete other training dives. To take advantage of this option, student divers must complete the knowledge development portion of the Enriched Air Diver course prior to making either of the required enriched air dives.
The way I see it, there is no minimum number of dives beyond the Open Water certification. Additionally, it seems that the certification dives may NOT be combined with Open Water certification dives. Finally, if your O/W instructor was a freak and taught the Wheel, then you will need a little training on the use of the table format of the RDP prior to an Enriched Air course.