There are many financial rules, regulations, and procedures that PahPal must follow. There are also other polcies and procedures which PayPal develops to protect it's business and the funds which everyone entrusts to PayPal. These polices and security models will not be disclosed by PayPal in order to protect it's own business.
One can only contemplate what it is important. I think that the PayPal user's credit rating and financial trustworthiness would be extrmely important so a use which has a great credit score and documented history of fiancial soundness would have shorter holds. New users also have not developed a financial history with PayPal and PayPal would have much longer holds, especially for large sums of money. PayPal could also consider your total funds avaiable based on any public information and credit reports.
If you attempt to circumvent PayPal internal security model, you could have your account closed.
It's important develo a financial history of trustworthiness before moving to large sums of money.
