I'd say yes, they should pay an extra premium for the source code. Regardless of the reason for wanting it, once they have it, they can customize it and rebuild it [if they have the development tools]. Most applications that I've used that will distribute source code have such a premium.

There are two clauses I would definitely add to the source code contract:

1. A clause stipulating that if any bug fixes are required and the bug can be attributed to changes they made [easy enough to determine with a file comparison tool], then there would be a hourly charge for this fix. [of course, if it can be attributed to your company's code, then whatever agreement you have currently would still be in effect].

2. They have been granted the right to customize the app and use it as per the original licensing agreement [e.g., #seats, #sites, etc.]. However, they have not been granted rights to resell or redistribute the application, as delivered by you or as customized by them.

>A client asked us to have access to the source code of our app they are using.
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>The thing is that this app is made for a vertical market. So there is no way that they'll get the source code right away.
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>What would be the best thing to do for everyone is to make the source code available in case something happens to the company and that they end-up with nothing.
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>That's the situation they want to avoid.
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>Should they have to pay a premium because right now they pay for a fair amount considering that the app is also sold to other businesses. If they get the source code then it's another thing because then the amount they paid (license) would'nt seem to be enough to get all the source code.
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>Now what do you think would be the best deal for everyone?
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>What should be considered in that kind of deal?
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>What kind of clauses?