Synchronisation Numbers iOS Mac OS X Yosemite via iCloud

The synchronisation of 'Numbers' spreadsheets between my systems (iOS 8.1.2 (12B440)/Mac OS X 10.10.1) via iCloud doesn't work smoothly.

Problem:

Especially when I update the spreadsheet in Numbers my iPhone, Numbers on my MacBook Pro won't show these changes immediately.

I haven't found a way to force the Mac to synchronize, yet. Is there one?

Workaround:

But when I go to the iCloud website and do some changes in the spreadsheet there, Numbers on my Mac does synchronise.

What am I doing wrong? Thank you very much for you answers! Konrad