The issue over late service of optional Replies in detailed assessment proceedings rumbles on. I cannot comment on whether the Senior Courts Costs Office has developed a “policy” line on this point (other than referring you to paragraph 19.5 of the Senior Courts Costs Office Guide 2013) but can report on a recent decision before Master Gordon-Saker.
Claimant made an application for permission to rely on Replies served out of time. Application dismissed with costs to the Defendant. Timescales set down in rules are there to be followed. No good reason put forward for late service. The hope that the cost of drafting Replies might be avoided by a negotiated settlement was not a “good reason”.
None of this is to suggest the parties may not agree sensible extensions between themselves for service of Replies.
The lesson is that if you wish to serve Replies after the date provided for by the rules, agreement should be reached before the deadline passes. If you wait until afterwards, you will have an uphill struggle.