Celestar,
Lauderdale is correct that your circles are your check - in my opinion it is completely unnecessary to have still air plogs and I have never known anyone else do this - unless there is perhaps another reason?
Your flight plan will have a summary that details the diversion time and the critical fuel scenario - this should really be all the thinking you need to do.
The circles are based around a rule DISTANCE and this is fixed according to your approval. All you need to do is, as you said, stay within these circles and have enough fuel to go to either ETP/ERA.
Where you WOULD view the wind or use actual wind is when selecting WHICH airfields to use. For example, if you were routing UK-Antigua (ANU)on 180mins (1200nm) and using just TER vs ANU as your last ETP set, and FDF as your alternate, you would normally be carrying lots of critical fuel.
Therefore, you want to add another ETP set to break up the long 'leg' that is TER vs ANU - so you add BDA and use TERvs BDA and BDA vs ANU. This is normally great and does the trick, except when your route takes you further east towards the Canaries OR if there is a really strong westerly wind making the diversion time to BDA a long one and having the effect of pushing the ETP back up the route to where it was when you were using TER vs ANU.
The answer in this scenario would be to try TFS vs ANU as the winds would not have the same effect on the location of the ETP on this pairing - therefore the forward/backward diversion would be farther down your route and therefore your ETOPS scenario is based on less time at 10000ft and therefore reducing the likelihood of carrying crit fuel
As with any rules, it depends how it is written and how it is interpreted but question your manager to justify the process - ask them why you have to complete the still air plog.
You mention Jetplan so I guess your employer is a Jetplan customer. Jetplan has a significant ETOPS database and there are many options and configurations, other than just your route, that might mean the summary time on your plan exceeds the rule speed yet does not break the circles.
For example, if you bias the distance by 50nm allowing a turn in either direction then your diversion time/fuel will increase yet the actual routing you take remains the same.
I hope this helps