I am preparing an IL tax return as part of an individual return with over 20 state returns.  There are several K-1s which are partially sourced to IL.  One also has IL additions and subtractions for bonus depreciation because IL decouples from Federal.  On the Federal level, for simplicity, let's say the net passive losses from IL sources total $10,000 and because passive losses exceed passive income on the federal level are partially disallowed and carried forward on the Federal 8582.  However, for Illinois purposes there is a net add back for bonus depreciation of $15,000 which results in $5,000 ($10,000 federal loss plus $15,000 of bonus depreciation add back) of passive income from IL sources.  However, LaCerte is disallowing the full $10,000 of IL source passive losses that were partially disallowed for federal and fully taxing the $15,000 of IL net additions.  This doesn't make sense to me.  Aren't the additions considered passive income and shouldn't the $10,000 of passive losses be available to offset the $15,000 so that the net income taxed in IL is $5,000 and not $15,000?

Any thoughts on this would be much appreciated.