Will Transfer of Vignette shorten my 2 year stay??

[gookenhaim]

Hello,
I applied for Tier 5 Youth Mobility Scheme visa.
But because of personal reason, I want to postpone my departure date(arrival date in the U.K.).

However, I heard a rumor that if I transfer my visa date of arrival,
It will deduct my 2 years of visa by the number of dates I used for postponing my intended date of arrival, making my 2 year stay shortened.
Is it true? (I don’t want to postpone my arrival date if it has the effect of shortening my 2 year stay)
Thank you for reading this and helping me.

[CR001]

Yes it will shorten your period you can stay.