Calculating Free Buffer Wait

Hi,
Currently we are calculating Free Buffer Wait with following formula:
SQL> select NAME,VALUE from V$SYSSTAT where NAME in ('free buffer inspected', 'free buffer requested');

NAME VALUE
-------------------------------- ------------
free buffer requested 3194990
free buffer inspected 3138511


% Free Buffer Wait=
(free buffer inspected*100)/free buffer requested

Sometimes its going far beyond 100%(even upto >150 also).

Is this formula correct?
Can this be considered as a normal behavior?
Please do let me know.

Thanks,
Pallavi.

Wouldn't it be:

% Free Buffer Wait=
(free buffer inspected/free buffer requested )*100

Hi,

The result will be same obviously,as for * and / the order does not matter.

What's the value for "dirty buffers inspected"?

Tamil