DateHelper.fromNow() returns 11 months instead of 10 for 319 days

The Moment.fromNow() spec says

45 to 319 days | MM | 2 months ago ... 10 months ago

implying that a timespan of 319 days should return "10 months ago".

The implementation in DateHelper returns "11 months ago" for this.

https://github.com/bennadel/JavaScript-Demos/blob/master/demos/date-helper-angular11/src/app/date-helper.ts#L271

I was curious if this was a known deviation from the spec?