Actually, that is part of the FMLA (Family Medical Leave Act).
With the usual caveats that no single part of UPS (geographically) seems to handle issues the same
, at least in my neck of the woods disability pay starts (if they don't deny it) on the fourth day off for illness and first day off for injury.
Professional medical treatment is required from day one to get paid, but doesn't guarantee payment.
There is a disturbing pattern being seen in my local building and from sporadic discussions with fellow UPS stewards in the state that the current disability handler (Broadspire) is denying an unprecidented amount of claims.
One of the more connected BA's in the state is collecting incidences of unwarranted claim denials.
Even if you do everything right and there are no hitches, delays or denials don't expect any payment for at least a month from the inception of your claim as the wheels turn slow and the excuses (check is in the mail, didn't get the fax, something else needing signing, etc. etc.) mount.
As far as the vacation time issue, planned disability enters the FMLA (Family Medical Leave Act) laws where you can take up to twelve weeks off for serious medical issues for yourself or someone close to you.
Contractually in the Central States supplement the company is allowed to force you to use up all but one week of vacation if they so wish.
This will occur for a "planned" disability like a scheduled surgery, etc far more often than an "unplanned" disability such as a back "going out" temporarily or a serious case of pneumonia, etc.
Any official time off will trigger the FMLA and COBRA laws to initiate paperwork to you giving you notice of your rights and choices now a days.