As far as I know the EEA procedure does not account for time spent under other type of Visas. Procedure is as follows:
1. Applying under EEA2 will give you initial residency for 5 years.

2. After 5 years you can apply for Permanent Residency under EEA4.

Legally the processing shall not take more than 6 months, however UK BA is casually disregarding Article 10 of EU directive 2004/58/EC and current processing time is spreading well over a year.

Good luck. Eric

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Act on EEA residency application delays by signing the petition:
http://petitions.number10.gov.uk/EEA4-Residency/