Hi Ibrahim
I can relate this statement to Internal order management.
In general within CO,apart from Line item update, data is also updated in Totals table where data is summarized based on common characters/dimensions / Amounts are totaled and can be used for fast processing of data... for eg in Report painter. Line items if exist are linked by Object number
Examples of Totals table =
COSS is for internal postings (activities, allocations)
COSP is for external postings
GLPCT - Profit centers
GLT* - GL data
CE3XXXX - CB-COPA
Aggregation happens based on certain fields where CO partner (like Partner Profit center, Partner Order etc) is also one of them. So if this is made active in Internal orders while defining Order type (in control parameters), this will add generation of additional characteristic and hence number of total records will also increase. Hope this answers your question.