Seen this binary date format?

Question

3/10/2008 = 1822556159

2/10/2008 = 1822523391

1/10/2008 = 1822490623

30/09/2008 = 1822392319

29/09/2008 = 1822359551

This is all the

Answer 1

September 30th 2008

1822392319 = 0x6c9f7fff
0x6c = 108 = 2008 (based on 1900 start date)
0x9 = 9 = September
0xf7fff - take top 5 bits = 0x1e = 30

October 1st 2008

1822490623 = 0x6ca0ffff
0x6c = 108 = 2008
0xa = 10  = October
0x0ffff  - take top 5 bits = 0x01 = 1

It's anyone's guess what the remaining 15 one-bits are for, if anything.

EDIT: by take top 5 bits I mean:

day_of_month = (value >> 15) & 0x1f

Similarly:

year = (value >> 24) & 0xff + 1900
month = (value >> 20) & 0x0f