Apple's heavy focus on the iPad Pro's enterprise side may have encouraged many professionals to dream of powering their presentations with the point of the Apple Pencil or wording those documents with the tablet's new Smart Keyboard. They can do all of that, just not with the free version of Microsoft Office.

It's the size of the new 12.9-inch iPad Pro that's the problem here. Microsoft has a cut-off for tablets, according to reports. Microsoft doesn't count any tablet above 10.1 inches as a "true mobile device."

The Android version of Office's EULA (End-User License Agreement) explicitly details the size restriction for displays.

"The free Microsoft Word app provides a core experience for viewing, creating and editing docs on devices with a screen size of 10.1 inches or smaller," reads the EULA for Android. "You can unlock the full Word experience with an Office 365 subscription."

The language isn't as declarative in the EULA for the iOS version of Office; however, based on reports, the same restrictions apply to Apple products.

Microsoft Office will still be available to devices with displays larger than 10.1 inches; it's just that the owners will have to pay Microsoft to run the software with all features unlocked. An Office 365 subscription will cover that.

This is an interesting narrative, where Microsoft jabs Apple and the iPad Pro by making the door too small for the tab to fit through, at least without paying tribute. But Microsoft's 10.1-inch cutoff is consistent with remarks made by the company's CEO last summer.

When trying to explain to investors what the Windows 10 experience would be like, Microsoft CEO Satya Nadella said the company had evolved its business model for its operating systems going forward.

"Now, Windows licenses are $0 for any OEM building a device less than 9 inches," said Nadella.

It does not appear Microsoft is taking a shot at the iPad Pro, as there are plenty of tablets that measure more than 10.1 inches. However, it does put the company in a great position to push its own hardware.

With a refreshed Surface expected to show its 12-inch face at Microsoft's Windows 10 devices presentation next month, a complimentary subscription to Office 365 could make the Surface Pro 4 even more enticing that iPad Pro and the Surface Pro 4 is already expected to be much cheaper than Apple's next tablet.