CRA's Schedule 3 only allows for 2 entries in the Qualified small business corporation shares section. The only option for additional lines for QSBC shares pertains to deferrals (Section 3).
If you have more than 2 entries for Qualified small business corporation shares, please contact CRA directly to determine the proper way to report the additional entries.
When I called the CRA to ask this - they said I had to refer to the software company as it wasn't to do with them, but had only to do with your program? I also have 3 entries needed under Sec 1 on the Sch 3 - but your help box says to use Sec 3 for additional lines which they said NOT to do (just sharing)
Unfortunately, the S3 itself from CRA only contains 2 lines. Having more than 2 entries in this section must be rare in the eyes of CRA.
I ran some tests in TurboTax Online (rather than desktop/download). In TurboTax Online, there is no limit for number of entries for the S3.
Since TurboTax Online is free to try (pay only when you're ready to file), take it for a test drive here www.turbotax.ca.