Taussig's "Tariff History" tells a different story. According to his numbers, the tariff revenues for FY 1862 (which would have started two months after the Morrill Tariff went into effect), were only slightly off those of FY 1860 (1860: $52.7 million, 1862: $46.5 million) and by FY 1863, they exceeded those antebellum. Even more telling, tariffs weren't reduced at the war's end, and yet in last half of the 1860s, tariff revenues shot up to triple or quadruple their pre-war levels. This at a time when, to hear your side tell things, the south was too beaten and impoverished to buy much of anything, imported or domestic.
Like some others here, you forget about inflation and what it tells about Taussig's figures. Here are some figures on net imports in 1860 dollars from an old post of mine to you as Heyworth in 2005 [Link, if you want to check it].
Tariff rates are from Table 1 of Taussig's The Tariff History of the United States, 1910 edition: Taussig.Yearly customs income is from Table 3 of Taussig. Same link as above. Actually, income from collected import duties was a bit lower than Customs income, but I'll use the higher figures.
Inflation rate was from Inflation Rates. I've seen higher rates than these posted for the period, but I'll be conservative and use these.
After applying the tariff rates to the revenue to determine the value of the imports, I then adjusted the number by the inflation figure. I find that the value of imports to the North relative to the total 1860 import value was:
1860: 1.00
1861: 0.82
1862: 0.50
1863: 0.52
1864: 0.54
1865: 0.38
You're not alone. My memory isn't as good as it used to be either. Here is some more information from my old spreadsheet:
Yr ............Tariff inc.........Inflation ........ Tariff Inc in 1860 $ ...... Tariff rate, %
1860 ......... 52.7 ............ 100 .................. 52.7 ................... 19.67
1861 .......... 39 .............. 101 .................. 38.6 ................... 18.84
1862 ......... 46.5 ............ 113 .................. 41.2 ................... 36.19
1863 ......... 63.7 ............ 139 .................. 45.8 ................... 32.62
1864 ......... 96.5 ............ 176 .................. 54.8 ................... 36.69
1865 ......... 80.6 ............ 175 .................. 46.1 ................... 47.56