Yes, it could be. The reason depends on several factors. One could be that with an 8K page size you were near the limit on rows per page. When you went to 16K, you reached the max rows per page and the rest is wasted space.
You need to mention what type of tablespace it is/was. Is the row count growing at a larger rate also?
Please see "Maximum records per page for a regular table space" or "Maximum records per page for a large table space"
(again, Andy wrote "You need to mention what type of tablespace it is/was. ...")
in Table 7. Database Manager Page Size-specific Limits.
sorry, you are right, the type of tablespace old and new is regular DMS tablespace.
the avg row length is 410, so in old tablespace (8k)every page occupied ~ 20 rows and in new tablespace(16K) every page occupied ~40 rows, do you think do we have any waste space ? but I read somewhere at index portion may be we have waste space. does it make sense ? table has 100 mil recoreds with 10 indexes.
really appreciate in advance for your help.