That sucks for you. I've been working at Microsoft for about 4 years. First 2 years as a tester, and the latter 2 years as a dev (still a dev). When I was a tester, I coded 4 days a week with 1 day a week for other investigations (live site issues, meetings, etc.) As a dev, the ratio haven't changed. I still code at least 4 days a week (80% of the time) with 1 day a week for meetings, investigations, documentations, etc. We have a separate operations team that carries pagers. They will do their investigation before I get called. For past 6 months, I got called once. Just in case you are wondering, I work under the Windows Live org.
I suspect the type of code you write. As a dev I'd expect you to write code that ships to customers. As a tester you write test code and harnesses. Stuff the customer never directly sees.
I think I can honestly say that at ever company I've run or been a manager of influence we've had more lines of test code than product code. Yet I'm still surprised when people say "testers code?"
