Funny thing about Poisson Processes: Every day you don't stake, you still have 100,000 days to go.
Here's a fun thing:
Pick a random point in time, then:
A) the average amount of time from that point to the next CLAM block is 1 minute
B) the average amount of time from that point to the previous CLAM block is also 1 minute
C) the average time between CLAM blocks is also 1 minute
Wouldn't you expect A + B = C? Yet A, B, and C are all 1 minute.
I don't believe that's a valid equation for the problem.
The above is the kind of math politicians use...

If X is the time of the block picked.
A is the time of the next block
B is the time of the previous block
C is the average block time.
Then
(1+( ( ((X+A) + (X-B)) /2) - X)) = C
should give you C as the average block time.
EDIT: Even better if your already doing the time offset math.
(A+B) / 2 = C