Though Microsoft is seeing some encouraging growth for its Windows Phone 8 smartphones in the mobile market, it does not appear that its tablets are faring as well.

DigiTimes today reported that retailers saw sales of Windows 8.1 tablets in October that are well below what was expected – 20% to 30% lower than estimates, even. The report’s unnamed “sources from channel retailers” blamed the slow sales, unsurprisingly, on the popularity of Android tablets and even on the declining PC market.

The report also warns that slow sales of Windows tablets could lead to “inventory issues” next year. The cryptic phrase more “inventory issues” no doubt refers to the $900 million worth of Surface tablets that Microsoft had to write-off at the end of its second quarter this year.

DigiTimes’ sources point to falling prices of PCs and Android tablets as major obstacles for Windows tablets. The report predicts that Windows 8.1 tablets will start to drop drastically in price starting in December, with some devices getting discounts as large as 20%.

These figures also might not bode well for Windows 8.1 as a platform. Last year’s release of Windows 8 was largely a failure, with the OS now running on less than 10% of PCs. Windows 8.1 is meant to correct the errors of Windows 8, improving design and bringing back the platform’s famed Start button. Anticipation was also building for businesses still using the soon-to-expire XP to upgrade their PC infrastructures this fall. However, if not even tablet users are embracing Windows 8’s tile-based user interface designed specifically with touchscreens in mind, it seems far-fetched that businesses would want their employees using the new OS.