Does sp_addtabletocontents Use Precomputed Partitions I am using merge replication in SQL 2012.

When I bulk insert rows into a table, and run this stored procedure to add references into the merge tracking table,

sp_addtabletocontents

Is that missing out on precomputing the partitions using the precomputed partition optimisations?
Intriguing question... as long as you have an actual scenario to apply it to it wouldn't be too difficult to figure out.  Perform your BCP process, run sp_addtabletocontents and then before the subscriber syncs verify the existence of the records in the MSmerge_current_partition_mappings and MSmerge_past_partition_mappings tables.  

According to this technet article that is where the partitioning data for each row that has been changed is stored post change/pre sync.  Look into the article for deeper information and the manner in which the table structures are organized within the process.  The link provided is for SQL 2008 but if the table structure is the same its a safe bet that the pre-compute logic is close enough to answer your question.

I am not an expert on precomputed partitions but it seems to me that it would have to take advantage of the precompute process (if enabled) otherwise it wouldn't sync these records at all.