Bitrix24 assumes a limit of 2 requests per second when accessing the API. If the limit is exceeded, the request is not executed, the API returns an error about exceeding the limit. As a result, some of the goods did not receive the updated value of prices and quantities. Now the script "sleeps" 0.5 seconds after each executed request. It takes 2 requests to update the price and quantity. Each attribute also requires 2 API requests. Accordingly, updating the product data now takes at least 1 second, as well as another 1 second for each attribute.
It will take about 1.7 minutes to update the data of 100 simple products.