Form 3921 ONLY shows ALL ISO exercises that happened during the tax year.  Box 14 of the W-2 ONLY shows the bargain element related to the current year sale of the shares exercised in the SAME year.  If Box 14 includes an amount with the ISO notation next to it, it means it is the bargain element for shares EXERCISED and SOLD in the same tax year.  The bargain element for the shares execised, BUT NOT sold in the same tax year, will be included on Form 6251 Part I, Line 2i for AMT purposes.

Please note, the amount in 14 of Form W-2 is already included in Box 1 wages.  It is highlighted because that amount is basis for the shares sold in the same year.