Line 22 is for U.S. Treasury bonds, bills, notes, etc. (Not Illinois bonds)
Lines 34 is for Illinois tax exempt interest.
Tax treatment is quite different for each line.
Instructions for line 22 states "If the mutual fund invests in U.S. government obligations and non-exempt obligations, your deduction is the distribution received from the mutual fund attributable to the U.S government obligations, as determined by the mutual fund"
Conversely, line 34 does not allow this deduction for Illinois bonds, except for specifically named bonds.
