Hi Gavrav,
If your on BPC NW 10, version. If any data changes then no problem for your BPC side.
If any structural changes happens at ECC side like Hierarchy design adding or removing extra nodes, same changes need to be done BW side. other wise BW data may be inconsistency. for BPC wise there won't be any issue.
Ex: cost center/Material have maintained any hierarchy structure at bw side and added new cost center/material at ecc side, same changes need to be at BW info object level. For BPC won't effect but bw will effect. so you need to take about BW changes to.
Thanks