diff --git a/src/ivfflat.c b/src/ivfflat.c
index 5c5ff07..a35f6e8 100644
--- a/src/ivfflat.c
+++ b/src/ivfflat.c
@@ -115,17 +115,22 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 
 	startupCost = costs.indexTotalCost;
 
+	get_tablespace_page_costs(path->indexinfo->reltablespace, NULL, &spc_seq_page_cost);
+
 	/* Adjust cost if needed since TOAST not included in seq scan cost */
 	if (costs.numIndexPages > path->indexinfo->rel->pages && ratio < 0.5)
 	{
-		get_tablespace_page_costs(path->indexinfo->reltablespace, NULL, &spc_seq_page_cost);
-
 		/* Change page cost from random to sequential */
 		startupCost -= costs.numIndexPages * (costs.spc_random_page_cost - spc_seq_page_cost);
 
 		/* Remove cost of extra pages */
 		startupCost -= (costs.numIndexPages - path->indexinfo->rel->pages) * spc_seq_page_cost;
 	}
+	else if (ratio < 0.5)
+	{
+		/* Change some page cost from random to sequential */
+		startupCost -= 0.5 * costs.numIndexPages * (costs.spc_random_page_cost - spc_seq_page_cost);
+	}
 
 	/*
 	 * If the list selectivity is lower than what is returned from the generic