We just went through the whole process, and it went like this: we signed the Limited Exhibition Agreement, which is the older form of the Ultra Low-Budget Agreement. We showed at festivals and had a limited theatrical release, then we got a DVD distribution deal.
When you get any kind of distribution, which you're not allowed to do under the ULB Agreement, you have to UPGRADE to a higher level of contract. If you've had a theatrical release, you upgrade to the Modified Low Budget Agreement, and you have to pay your actors back pay on that rate (which is about $500 a day plus overtime and pension and health), and you also owe them residuals. The catch is, you are required to screen your film in at least one NON-ARTHOUSE THEATER. SAG will tell you if the theater is considered an arthouse theater are not. I'm not clear on what their parameters are, but I think that most theaters that screen independent films are considered arthouse theaters, including the Cinema Village, the Sunset 5, the Landmark Theaters, etc. By some freak of luck we happened to screen at one AMC Theater in Montreal, so we were safe.
If you can't prove that you screened at a non-arthouse theater then you are bumped to the next level, the Independent Television Producer's Agreement, which is I think around $700 a day. That's for an 8 hour day. So if you had a 12 hour day where you paid the actor $100 plus 4 hours overtime and it cost you $175 plus 13% pension and health at the time, now you owe that actor overtime on $700, so that would be $1225 for that one day, plus about $160 for pension and heath plans and about 15% more that the payroll company takes. So you are looking at about $1500 a day for any actor that signs any type of SAG contract if you plan to release that film on DVD, even if you release it yourself. And you are liable for residual payments on your gross sales of about 5%, on which you also have to pay a payroll company and pension and health benefits.
If you release your DVD without telling SAG and they find out, they will sue you for breach of contract and make you pay the highest going rate or they will take you to court.
And one more thing: if you are producing a SAG movie and acting in it yourself, make sure to sign the SAG paperwork and time sheets, or else you will not be entitled to any residuals yourself, even if you were the lead and everyone who signed the SAG contract had only one line. The SAG actors will split the residuals pie between them, and no one else in the cast is entitled to anything. You can't do this after the fact.
I scoured the web for this kind of information and couldn't find it, so I hope this helps some of you who are planning to use SAG actors in your films. Good luck.