On Tue, Nov 24, 2015 at 4:36 AM, Peter Todd via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> The downside of BIP68 as written is users of by-height locktimes have 14
> bits unused in nSequence, but by-time locktimes have just 5 bits unused.
> This presents an awkward situation if we add new meanings to nSequence
> if we ever need more than 5 bits. Yet as shown above, the extra
> granularity doesn't have a practical benefit.
>
>
> Recommendation: Change BIP68 to make by-time locks have the same number
> of bits as by-height locks, and multiply the by-time lock field by the
> block interval.
>

I think you might be referring to the old specification. I believe this was
brought up before and the specification was changed so the same number of
bits were used for by-time and by-height. Please see
https://github.com/bitcoin/bips/pull/245

However, I am glad you came to the came conclusions independently because
"re-invention" often confirms good ideas :)