Publisher Activision’s Call of Duty: Ghosts was the best-selling game in the important month of November, but this doesn’t mean the modern-military shooter met expectations.

Call of Duty: Ghosts sales were down 19 percent year-over-year compared to Call of Duty: Black Ops II, according to market-analysis firm Cowen & Company. That wasn’t entirely unexpected. Activision warned investors that many gamers were holding off on making a purchase while they prepare to transition from older systems like Xbox 360 and PlayStation 3 to the next-gen Xbox One and PlayStation 4 consoles.

The publisher told investors that it anticipated that Call of Duty: Ghosts sales would come up short of what Black Ops II did. Cowen analyst Doug Creutz thinks that a closer look at the numbers reveal that things are even worse for Call of Duty: Ghosts than what the Activision guidance suggests.

“Upon further reflection, we think the [Call of Duty] numbers are a bit more troubling than they first appeared,” Creutz wrote in a note to investors. “While the year-over-year gap is only 19 percent thus far, that includes two extra weeks of sales for the 360 and PS3 versions [of Black Ops II]. Against 2011’s [Modern Warfare 3], where the difference is only one week, the title is down 32 percent life-to-date.”

Call of Duty: Ghosts debuted on Nov. 5 for Xbox 360, PlayStation 3, Wii U, and PC. Last year, Black Ops II didn’t release until Nov. 12. In 2011, Modern Warfare 3 hit stores on Nov. 8. That means that even with more time to sell, Ghosts couldn’t keep up with its two most-recent predecessors.

Of course, Activision later released Ghosts for PlayStation 4 and Xbox One on Nov. 15 and Nov. 22, respectively, and it did a significant portion of its sales on those devices. But those new machines don’t have the player base to help Ghosts make up the difference, and Creutz has a gloomy outlook for this particular installment of the Call of Duty franchise behemoth.

“We don’t think it is out of the question that the title could wind up comparing down 20 percent to 25 percent year-over-year [to Black Ops II], which is appreciably worse than the down 10 to 15 percent that we think is baked in to guidance.”