Tier 1 Enterpreneur visa extension- Job creation

I got my enterpreneurial visa on Oct 2013 and I will need to renew it next year.
I have hired 2 part-time for 3 months (from Nov 2014-Jan 2015)
Both of them left the post and now I am hiring a full time.
I am wondering:
1. Can those 2 part-time be counted for 1 full-time? (They work 15h/w each)
2. I hired a full time from Feb this year, and wish to hire her for 18 months (till August 2015).
So I will need another employee. Since my previous 2 employees only worked for me for 3 months, does it mean that I have to hire 1 full time for 3months , or 1 part time for 6 months, or 2 part times for 3 months in order to meet the requirement?
Or, I will have to hire 1 fulltime for 6 months?
Or, hire 1 full-time for 1 year? (according to point 85)
The point confuses me is that in TIER 1 (ENTREPRENEUR)
Version 10/2013 point 85 it says:
85. Where you have taken over or invested in an existing business, your services and investment must have resulted in the businesses providing, between them, the equivalent of two extra full-time jobs during the period when you held leave as a Tier 1 ( Entrepreneur) migrant. These jobs must have been taken by people who are settled in the UK and those jobs must have existed for at least 12 months each.

Where in point 91 it says:
91. EXAMPLES: We would consider the following as acceptable employment:
• The working hours of two part-time workers can be combined to add up to 30 hours a week or more and form the equivalent of one full-time post.
• A worker who is employed for part of a year and then leaves the job can be replaced by another worker so that the employment as a whole adds up to 12 months. However, if there is a gap between one worker leaving a post and another worker starting employment, the period when the post is not filled will not be counted. Only periods during which a worker is employed in a post will be considered.
• A single worker can be employed for 24 months. The employment can also be made up of a six-month period for one worker and an 18-month period for another.
• If four workers are employed for 26 weeks (six months) each, their hours of employment may be added together.

Can anyone help?
Thank you very much!

Izzie