It's more like the overshipment in 2013 heavily influenced Q4 FY2014 and Q1 FY2015 shipments. Heck, actually, I think last quarter shipments have been "limited" as well (i.e. pretty near to actual sales), probably due to New 3DS launch incoming in the West and not wanting to have too many old models on shelves.
Not that sales haven't been down YOY, mind you, but what happened last year had a lasting effect on shipments this year.
Just to get a clearer idea of what I mean, going by the numbers posted by Bruno MB
Nintendo 3DS
3rd Quarter, Fiscal Year 2015 shipment
Japan - 2,090,000
The Americas - 1,500,000
Other - 1,390,000
Total - 4,980
3rd Quarter, Fiscal Year 2014 actual sales
Japan - 1,598,600
The Americas - about 1,460,000 (from US)
Other - we have no concrete numbers, but I'd estimate 1 million at least, considering it's the Holiday season
Total - 4,058,600 at least. Probably more like 4,200,000 - 4,250,000, but let's stay with the minimum for Other
3rd Quarter, Fiscal Year 2014 shipment
Japan - 2,430,000
The Americas - 2,930,000
Other - 2,400,000
Total - 7,760,000
3rd Quarter, Fiscal Year 2014 actual sales
Japan - 1,774,945
The Americas - around 2,322,000 (for US)
Other - again, unfortunately there aren't concrete numbers for overall Europe. However, sales were surely higher than 1,000,000, and I'd add surely higher than 1,500,000 as well, considering the overall retail perfomance in US. Probably more like 1,700,000 - 1,900,000
Total - 5,796,945 - 5,996,945, depending on actual Others numbers
I.e. sales surely dropped in the West compared to Q3 FY2014, we can't deny it. And it's a consistent drop. But it's also quite apparent how shipments have been far stricter to the actual sales (especially in the West), compared to what happened at the end of 2013. And I think stricter to what happened in the past years too (not in the same way as 2013 v.s. 2014, though, of course). Probably both because, despite Q2 being better in this sense, there were still units left on shelves to sell, and (I think the biggest factor) Nintendo didn't want to overship too many older 3DS XL and 3DS OG units with the launch of New 3DS (the model that will substitute the older 3DS SKUs) being near for the West. Thus, the YOY shipments drop is quite increased by this.