How to set up calculation in items in Zabbix?

Question

Zabbix

Essence of the question: there are several hypervisors for ESXi 5.1 and 6.0, monitoring is configured, the question arose: how to calculate the percentage of CPU load? Everything is done through the built-in Template Virt VMware Hypervisor template, there are two data elements (items): CPU frequency and CPU usage, which should show the average frequency on all cores and the average load on all cores, but on one of the servers, CPU frequency shows an average frequency of 2 GHz, which is correct, and CPU usage can go up to 8xCPU frequency - i.e. up to almost 16 GHz. How to win this is not clear.
I tried to create a data item like CPU cores * CPU frequency, calculation formula

last("vmware.hv.hw.cpu.freq[{$URL},{HOST.HOST}]") * last"(vmware.hv.hw.cpu.num[{$URL},{HOST.HOST}]")

- as a result, I received the message Macro {$URL} is not numeric, while the code

last("vmware.hv.cpu.usage[{$URL},{HOST.HOST}]") * 100 / last("vmware.hv.hw.cpu.freq[{$URL},{HOST.HOST}]")

works great and doesn't throw any errors.
How to achieve proper monitoring of CPU load - thoughts are over, the ESXi version on the problem host is 5.1.