technique for accommodating higher instep height than is ideal for a last and pattern of a lace-up shoe by lasting an upper a half size or more larger than would usually be used on that size last
Depending on how the pattern is graded, using a larger-sized upper can narrow the facing gap over the foot, allowing the wearer to lace the shoe over their foot without spaying the quarters apart to an unsightly extent.
Compare oversizing uppers.
Mismatching last and upper sizes usually isn’t the ideal way to address instep height fit, but can be a relatively straightforward way for made-to-order production lines that don’t modify lasts to accommodate small differences.