Downtime - practice stacking

Under the Practice rules, can you stack up multiple tests for the same skill during the same time period? (e.g. for a skill with a 1-month cycle, 2r/4d/6c, can you get 4 routine tests in 1 month by saying you spent 8 hours a day for that month practising it)
Or can you only earn “one test at a time” for a particular skill?

(Note: I do understand that you can stack up tests for multiple skills as per page 320, just wondering about the same skill)

Not for the same skill.