I'm following this pattern to make a sweater. For the gauge requirement, it states:
17 stitches and 31 rows = 4 inches in Seed Stitch
Then the schematic shows the front/back panels having a width of 20" each, and the pattern calls for 98 stitches each. But that comes out to
98 / 20 * 4 = 19.6, which isn't 17. It seems like this could mean the 17" measurement is unwashed, if the fabric is supposed to shrink.
But the pattern also says:
Seed stitch will grow when blocked. If you are concerned about the length, measure your gauge in seed stitch from a washed and blocked swatch and calculate number of rows necessary to achieve desired length after blocking.
Finally, a rough comparison of the sleeve length in the schematic (18" including cuff) with the pattern (1.5" cuff + 127 rows) would give
127 / (18 - 1.5) * 4 = 30.78, which is roughly the suggested gauge of 31, suggesting the fabric would be expected to neither shrink nor grow during washing.
My gauge swatch before washing is roughly the recommended 17x31, but given the above discrepancies I'm concerned that the measurements in the schematic won't be accurate.
Should I consider adjusting my needle size to achieve a washed size of 17x31? Or should I expect the schematic's measurements to be accurate even though they seem to disagree with the gauge recommendation? Are there any other techniques I can use to validate the sizing before I get too far into the pattern?
(This will be my first serious blocked garment where the sizing actually matters, so I'm also not sure how much leeway I will have to adjust the size during blocking. If it matters, the pattern recommends 2–4" positive ease.)