Two kinds of Metadynamics code writing

[Venthaul ZI]

Hello,

I am trying to apply a metad on my system and my original code is like this:

```

METAD ...
   LABEL=metad
   ARG=CV1,CV2,CV3,CV4
   SIGMA=0.05,0.05,0.1,0.1 HEIGHT=0.2
   BIASFACTOR=15
   TEMP=300
   PACE=1000
   FILE=HILLS
   GRID_MIN=-pi,-pi,-pi,-pi
   GRID_MAX=pi,pi,pi,pi
   CALC_RCT
... METAD
```
But I found that this would cause Plumed to spend too much time calculating the GRID and CALC-RCT, so I split it into two METADs like this:
```
METAD ...
   LABEL=metad_1
   ARG=CV1,CV2
   SIGMA=0.05,0.05 HEIGHT=0.2
   BIASFACTOR=15
   TEMP=300
   PACE=1000
   FILE=HILLS_1
   GRID_MIN=-pi,-pi
   GRID_MAX=pi,pi
   CALC_RCT
... METAD

METAD ...
   LABEL=metad_2
   ARG=CV3,CV4
   SIGMA=0.1,0.1 HEIGHT=0.2
   BIASFACTOR=15
   TEMP=300
   PACE=1000
   FILE=HILLS_2
   GRID_MIN=-pi,-pi
   GRID_MAX=pi,pi
   CALC_RCT
... METAD
```
I would like to ask whether these two ways of writing will lead to a difference in simulation? And the second method will generate two HILLS files, how can I do sum-hills processing properly?

Thank you!