Does sponsor certifying maintenance apply to dependents even if they are travelling separately?

I moved to the UK on a PBS Skilled worker visa two months ago, and my wife will be joining me very shortly. Today, when we were going through my CoS, I noticed that it mentioned a "Y" in front of "Tick to certify maintenance for migrant (and dependents if applicable). I knew that they had certified my maintenance, but I wasn't aware that it applied to my wife too. However, does this stay valid if my wife is applying over 3 months after my application? If not, would I need to provide bank statements - and do they need to be UK banks or can be submit statements from her local bank in our home country. Thanks

The sponsor's certification of maintenance in the CoS covers both you and your dependants irrespective of when the dependants travel to the UK. No further documents needed for your dependants.