In PhotoScan 1.2.5 build 2614 (64bit) on Windows 7 the getFloat dialog does not show the label text at all. Example:
answer = PhotoScan.app.getString(label='I can see this text in dialog', value="Hello")
answer = PhotoScan.app.getInt(label='I can also see this text in dialog', value=5)
answer = PhotoScan.app.getFloat(label='But this text is nowhere to be seen', value=0.5)