British Parent by descent, residence less than 3 years

Hello,
I have a query regarding registration of my children as British Citizen through MN1 form under section 3(2). My query particularly relates to British Parent by descent and residence requirement of 3 years before the child's birth.
Facts:
I am British National by descent and born abroad.
My Father is British National by Naturalization. He lived and worked in UK for 15+ years during 60s and 70s and was British National before my birth.
My Wife and 2 children are Non British.
I have only spent 2 years and 4 months in the UK while I was studying in university and working.
Is there a possibility that I can add the allowed absence of 270 days (9 Months) to complete the requirement of 3 years.
Hence the 2 years and 4 months stay (with no absence) can be considered a 3 year period with absence of 270 days.
Extract from the guidelines available on UKVI websites is presented below for reference:
Quote
The child’s parent must meet the residence requirements listed below, unless the child was born stateless.
The parent in question must:
• have lived in the UK for a continuous period of 3 years at any time before the child’s birth
• have been in the UK at the beginning of that 3 year period
• not have been absent from the UK for more than 270 days in that 3 year period
UnQuote
As per above extract I was in the UK at the beginning of the ‘3 year period’ and there is no requirement to be in the UK at the end of the ‘3 year period’.
So is there a chance that my children can qualify as per above information.
Regards

I think you can't claim "credit" for the allowed absences in advance of any absences, the actual residency period completed must be 3 years. Why not wait out the eight months remaining to complete three years?

Slight clarification in my query:
My stay in the UK started and ended 15 years ago, well before I got married and had children.

The law requires a residence of three years. It would make a mockery of the law if a residence of two years and a few month is assumed to be a residence of three years.

But in any case, if the children are younger than fifteen years old, you have the option of moving with them and the other parent to the UK, living with them in the UK for three years and registering them as British citizens under Section 3(5).

Also see this thread.

You could make the argument you have made above in a Form MN1 application for your children now. Even assuming that it does not engage the entitlement of Section 3(2), it may be considered under Section 3(1), at discretion. But keep in mind that even if it was granted under Section 3(1), your children, whether registered under Section 3(1) or Section 3(2) will also be British citizens by descent. And their children (your grandchildren) can't be registered under Section 3(2).