Only 4 reviews are displayed on product page instead of 15

Hello,

I’m using the latest version of WooCommerce Photo Reviews.

On my product page I have 34 reviews, but only 4 reviews are displayed initially, even though I would like to show 15 reviews per page.

I have already checked:

Settings → Discussion → Break comments into pages = 15
WooCommerce Photo Reviews settings
Cleared all caches

However, the product page still loads only 4 reviews before the “Load More” button appears.

Could you please tell me:

Which setting controls the number of reviews initially displayed on the product page?
Is there a filter, shortcode attribute, or PHP hook to change this?
Could this be caused by my theme (Shoptimizer), or is it controlled entirely by WooCommerce Photo Reviews?

I’ve attached a screenshot showing the issue.

Thank you!
Jozsef