Negative font sizes for h2, h3

[atomsmith]

When using Chrome Developer Tools, I noticed that h2 and h3 elements have invalid font sizes. These originate from the following declarations in configuration/nucleus/_typography.scss:

$h2-font-size: $core-font-size - 1.60 !default;
$h3-font-size: $core-font-size - 1.50 !default;

Since $core-font-size is 1rem, the compiled CSS is:

h2 {
font-size: -0.6rem; }

h3 {
font-size: -0.5rem; }

Should those subtractions be additions instead?