What my company does it to obtain the Accpac data ahead of time (if possible) and do a test conversion on our systems. That way we know if we should expect any issues when converting the live data.
It also gives us a chance to view the modules and suggest changes or upgrades if needed (usually this is only done if we are the business partner).
As with Ettienne, a lot of support is performed remotely and the size of the database makes a huge difference on time frame.
I don't find that an estimate of 5 days is unreasonable, although in my observations usually three days at the most. The extra time frame allows for adjustments in case of problems or larger database. Keep in mind that during conversion, no-one has access to Accpac.
When we perform conversions, we start as soon as we can on Friday and hope that everything can be completed by Sunday night so that the client is ready to go come Monday morning.
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