Significance of sub-sub-period (Pratyantardasha) in astrology

Hi! I am currently going through Rahu Mahadasa and Mercury Antardasha. Overall Rahu Mahadasa has been good for me. Mercury Antardasha started on 3/3/15 and is an unfavourable period for me. (Waiting for it to end )

However, I noticed that Rahu Pratyantardasha started last month and seems to "amplify" the negativities. I've had 2 car accidents, period, loss of finances, obstacles etc.

I never really paid attention to Pratyantardasha and only gave importance to Mahadasha and Antardasha but now I am curious on Pratyantardasha's power/significance. Does it also have much significance/importance as the dashas and buktis?

If anyone could help me understand it better, it will be really helpful. Thank you in advance.

The major-period covers an extensive span of time. Within it the sub-period covers a shorter duration and the inter-period (pratyantar) in the sub-period generally does not extend over more than a few months.
If an event happens during the inter-period, it has to happen in the sub-period and also major-period since that point of time would be covered by all the three periods.
Therefore these three periods will always show the same event. If two periods show an event and the third does not, the event cannot happen.
Suppose a child was born to an individual on 3/March/2014. If the periods have been calculated correctly this date will fall within all the three periods.
Many a time the time of birth is not accurate and the inter-periods go haywire. Therefore many astrologers do not go beyond the sub-periods and beyond the sub-period they depend on transits.

Thank you very much mathur dinesh sir!! Your post has been really insightful and helpful to help me in understanding the inter-periods, it's sensitivity and why astrologers hardly go beyond the sub-periods.