I came across this inconsistency while reviewing BIPs. Per BIP-0068, 16 bits of the sequence number are used for the relative lock time to allow for lock times of a year. Since Dash has a block time of 2.5 minutes (vs. Bitcoin's 10 minutes), the maximum block-based relative lock time is reduced by a quarter (2^16 * 2.5 min/block = ~113.75 days).

Time-based lock times remain the same as in bitcoin (~1 year) since the granularity was not changed.

Also, to maintain the relationship between the scaling of block-based and time-based lock time values described in BIP-0068, 18 bits of the sequence number would have to be used AND the granularity would have to be changed from 9 (512 seconds) to 7 (128 seconds). Doing this would result in the same maximum lock times for both time and block-based lock-times as bitcoin due to the factor of 4 between the Dash block time and Bitcoin block time.

At a minimum, these changes would have to be made at the following location in transaction.h, but I have not considered what other implications there might be:

• Sequence Locktime Mask - Change 0x0000ffff to 0x0003ffff
• Sequence Locktime Granularity - Change 9 to 7

One complication is the affect on any existing lock-times based on the current parameters if the mask and granularity were simply changed.