GPU_MAX_ALLOC_PERCENT only throttles 1 card

[aphex3k]

I'm using sgminer on mac OS High Sierra in a Mac Pro with dual AMD Radeon HD FirePro D700. When I export GPU_MAX_ALLOC_PERCENT=80 before starting sgminer, it only throttles one of the cards. The second card is going full 100%. I expect both cards to be throttled.

Am I missing something?

export GPU_MAX_ALLOC_PERCENT=80
...
[13:09:32] GPU0                | (5s):132.8M (avg):279.5Mh/s | A:0 R:0 HW:0 WU:119.707/m                                                                                  
[13:09:32] GPU1                | (5s):102.2M (avg):215.3Mh/s | A:0 R:0 HW:0 WU:51.873/m 

export GPU_MAX_ALLOC_PERCENT=100
...
[13:09:12] GPU0                | (5s):131.7M (avg):275.9Mh/s | A:0 R:0 HW:0 WU:119.507/m                                                                                  
[13:09:12] GPU1                | (5s):128.2M (avg):276.7Mh/s | A:0 R:0 HW:0 WU:115.386/m 

$ sgminer --version
sgminer 

$ sgminer --ndevs
[13:31:36] CL Platform vendor: Apple                    
[13:31:36] CL Platform name: Apple                    
[13:31:36] CL Platform version: OpenCL 1.2 (Sep 12 2017 16:28:17)                    
[13:31:36] Platform devices: 2                    
[13:31:36]      0       AMD Radeon HD - FirePro D700 Compute Engine                    
[13:31:36]      1       AMD Radeon HD - FirePro D700 Compute Engine                    
[13:31:36] 2 GPU devices max detected