Definitively, Yes.
SEO is a killer for 3D calculation time. Not a problem for a single or few objects, but significant for several objects using SEOs.
I did wrote a roof accessory using roof tiles, in which each tile used a SEO. My first concern was the low Polycount (20) of each tile.
It worked fine for thousands of tiles (that means thousand of SEOs), but 3D calculation time was a bit slow.
After a thread with Ignacio on this forum last summer, i realised how much SEOs can dramatically slow down speed.
I decided to change the SEO tile object for another one without SEO. Polycount is higher (98 ), but 3D calculation is really faster (8 x).
If your concern is speed, try to avoid SEOs, and model your parts with current tools (AC or GDL). They will always generate faster.