How can you have a Buffer cache hit ratio of 100% with PLE of 103?
Buffer cache hit ratio and Buffer cache hit ratio base are measurements for a very small timeslice. You just ran your query at times when the recent reads hit the buffer cache.

For proof, just look at the raw values over time - they go up and down.

SELECT *
FROM sys.dm_os_performance_counters
WHERE counter_name IN ('Buffer cache hit ratio','Buffer cache hit ratio base')


I would recommend a look at other metrics (perhaps sys.dm_io_virtual_file_stats?) to see what kind of IO you're driving.