Sure, if you are not going to trust IJ data I do not have much to add but then providing contrary data would be the responsibility of government agencies which they have not.
Secondly, while I suspect 15K is far to less number perhaps it might be tru for federal CAF, but we need to add state CAFs as well as Cook county alone seems to have seen over 23K instances over five year period.
IJ of course has an agenda to end CAF and without a doubt they will cherrypick data that suites their agenda, which is still better data that law enforcement which has far nefarious motives may provide.
My understanding $1.25B and $2.5B are per year numbers. But even if they are not, they are still 10x time more than your number.
ij.org is not the primary source, it does not reference the originals, and clearly has an agenda, so a different source is needed for the raw data.