Annual jabs - question. Do you have one of those wheel charts things??

[Fools Motto]

I am now getting more and more confused!

So, my yearling filly started her jabs this year.
Her first jab was on 21st April
Her second jab was 2nd June.
Her third jab 'should be between 150 and 215 days after her second' = Right?
So, thats anytime from October 27th til Jan 29th

BUT, ''I think'' the last 27 days of this period is for those just getting the booster, NOT for those who are getting the third instalment of the course?? So this means she has to be jabbed before the 2nd Jan??

If there is anyone clever out there, who may be able to say I am either correct or not, please shout.

My intentions are for both my girls to get their annual booster together, so I will be bringing my mares date forward by 3 or now possibly 4 months.
Originally, the vet said end of jan for both and all will be ok, but I am now not so convinced.

 

[fidleyspromise]

someone else can probably explain better and more accurately, but both vets (different) for my girls told me the second jab is 4-6 weeks after the first and the third is 6 months after the second.