The student of rhetoric will also tell you that the passive voice deflects more than just immodesty. It functions as an oblique way for the reader to slide over what might otherwise prove uncomfortable for the writer--asking "who came up with that 200M or 700M figure--kind of outlandish, don't you think"? There's a heap of "surmisin'" that slips by with the use of the passive voice.
It's not modesty at all. The science is the center of interest and any suitably equipped scientist should be able to reproduce the results if it is good science.
As to whether the passive voice is just as suitable for other areas such as the annual laboratory budget, well, that would be an affectation. But for science as a discipline, the passive voice should be perfectly acceptable.