[Fontinst] fontinst fontdsize variance?

[Karl Berry]

Hi Lars - thanks much for all the investigations.

    tftopl naively reports the latter

tftopl is just reporting what it sees, right?  Can't blame it for that.

    Yes; vptotf isn't all that detailed in its messages 

So maybe this is where the fix should lie: vptovf should not report
variances in design size up to <some amount>, because of the difference
between mf and tfm representations/resolutions.  Wdyt?

The discrepancy seems worth reporting to Knuth (for 2020 ...).  Whether
he'll deem it worth a reward, have to see.