Fathwa, - Something funny happened in my menstrual cycle�

Question:
A sister asked me about an issue and I thought I would put the
question to this website.
Answer:
Assalamu alaykum
In the Name of Allah the Inspirer to truth.
To answer this and other similar questions relatingto menstruation one
needs to keep the basic principles of menstruation in mind. Namely:
The minimum period for menstruation is three days (72 hours). This
means that if blood is seen for less than three days, it does not
count asmenstruation. The maximum period for menstruation is ten days
(240 hours). This means that if blood is seen for more than ten days,
it does not count as menstruation. A ladies habit ('aada) is the
length of her last valid menstruation. If she sees bleeding for more
than ten days then the length of her habit is considered
menstruationand what exceeds that is considered abnormal uterine
bleeding (istihada). For example, ifthe previous menstrual period
lasted 6 days, and the next time she sees blood for 14 days, she will
consider 6 of these days as menstruation (based on her habit) and the
other 8 days as abnormal uterine bleeding. She should have taken a
ghusl at thecompletion of day 10, even if there is bleeding. Seeing
that the bleeding goes over the maximum, she returns to her habit. All
the prayers missed from day 6 at the end of her habit to day 10 must
be made up.
It is not a condition that blood flow be constant during the menstrual
period. What is important is the first and last days it flows on and
all that is in between is counted as though bloodflowed though in
reality it might not have. For example, if she sees blood on the first
day and then the fourth day and then no more blood, this will be
treated as four continuous days of bleeding and will all be treated as
menstruation. The minimum length of apurity period between menstrual
periods is fifteen days. Whatever is seen during the menstrual period
is counted as menstrual blood no matter what colour it is. [Hashiya
al-Tahtawi 'ala Maraqi al-Falah, 1:199, Maktaba al-'Ilm al-Hadith]
These are the general principles that apply to most cases. A seventh
principle that can be derived from 3 and 4 above applies to the
specific case asked about. Namely; that an incomplete purity
periodbetween blood flows is treated as though blood flowed on all of
those days. An incomplete purity period is one that lasts for less
than fifteen days. This means that if a lady sees bleeding one day and
then no bleeding for 12days and then sees bleeding again, because the
purityperiod was incomplete as it was less than 15 days, she will
treat it as though she saw 14 days of constant bleeding. What does she
do in sucha case? She has to return to her habit as in 4 above. She
will have to calculate her menstruation and purity based on her habit
for bleeding and purity.
In the question above, from July 1st to September 24th there was no
complete purity period between bleedings and so she willtreat it as
though she bled constantly for those two months. To determine when she
will be menstruating and when not depends on her habit for
menstruation and purity which was not stated. If we take as an example
that her last menstruation lasted 8 days and her last purity lasted 20